diff --git a/database/db.json b/database/db.json index 5513ef3..bd53c07 100644 --- a/database/db.json +++ b/database/db.json @@ -82,6 +82,15 @@ "Known issues": "", "Released on": "Astromat", "URL": "https://zenodo.org/record/15015059/files/PGD_SiC_2025-03-10.csv" + }, + { + "Change": "1. Four PGD-IDs of duplicates retired.\n2. Renormalized data for Nicolussi et al. (1997) Science 277:1281 added.\n3. Data from the following references were added:\nNguyen et al. (2025) NatAs 9:1812\nMarhas et al. (2026) ApJ 997:275", + "Date": "2026-05-19", + "DOI": "10.60707/VZ7T-7628", + "Grains": 20502, + "Known issues": "", + "Released on": "Astromat", + "URL": "https://zenodo.org/record/20317007/files/PGD_SiC_2026-05-19.csv" } ] }, diff --git a/database/pgd_references.bib b/database/pgd_references.bib index 3fd48c1..907bf1f 100644 --- a/database/pgd_references.bib +++ b/database/pgd_references.bib @@ -1,8 +1,11 @@ @article{avilaTungstenIsotopicCompositions2011, - title = {Tungsten Isotopic Compositions in Stardust {{SiC}} Grains from the {{Murchison}} Meteorite: {{Constraints}} on the s-Process in the {{Hf-Ta-W-Re-Os}} Region}, - shorttitle = {{{TUNGSTEN ISOTOPIC COMPOSITIONS IN STARDUST SiC GRAINS FROM THE MURCHISON METEORITE}}}, - author = {{\'A}vila, Jana{\'i}na N. and Lugaro, Maria and Ireland, Trevor R. and Gyngard, Frank and Zinner, Ernst and Cristallo, Sergio and Holden, Peter and Buntain, Joelene and Amari, Sachiko and Karakas, Amanda}, - year = {2011}, + title = {Tungsten Isotopic Compositions in Stardust {{SiC}} Grains from the {{ + Murchison}} Meteorite: {{Constraints}} on the s-{{Process}} in the {{ + Hf-Ta-W-Re-Os}} Region}, + author = {{\'A}vila, Jana{\'i}na N. and Lugaro, Maria and Ireland, Trevor R. + and Gyngard, Frank and Zinner, Ernst and Cristallo, Sergio and Holden + , Peter and Buntain, Joelene and Amari, Sachiko and Karakas, Amanda}, + year = 2011, month = dec, journal = {The Astrophysical Journal}, volume = {744}, @@ -12,26 +15,58 @@ @article{avilaTungstenIsotopicCompositions2011 issn = {0004-637X}, doi = {10.1088/0004-637X/744/1/49}, urldate = {2023-01-26}, - abstract = {We report the first tungsten isotopic measurements in stardust silicon carbide (SiC) grains recovered from the Murchison carbonaceous chondrite. The isotopes 182,183,184,186W and 179,180Hf were measured on both an aggregate (KJB fraction) and single stardust SiC grains (LS+LU fraction) believed to have condensed in the outflows of low-mass carbon-rich asymptotic giant branch (AGB) stars with close-to-solar metallicity. The SiC aggregate shows small deviations from terrestrial (= solar) composition in the 182W/184W and 183W/184W ratios, with deficits in 182W and 183W with respect to 184W. The 186W/184W ratio, however, shows no apparent deviation from the solar value. Tungsten isotopic measurements in single mainstream stardust SiC grains revealed lower than solar 182W/184W, 183W/184W, and 186W/184W ratios. We have compared the SiC data with theoretical predictions of the evolution of W isotopic ratios in the envelopes of AGB stars. These ratios are affected by the slow neutron-capture process and match the SiC data regarding their 182W/184W, 183W/184W, and 179Hf/180Hf isotopic compositions, although a small adjustment in the s-process production of 183W is needed in order to have a better agreement between the SiC data and model predictions. The models cannot explain the 186W/184W ratios observed in the SiC grains, even when the current 185W neutron-capture cross section is increased by a factor of two. Further study is required to better assess how model uncertainties (e.g., the formation of the 13C neutron source, the mass-loss law, the modeling of the third dredge-up, and the efficiency of the 22Ne neutron source) may affect current s-process predictions.}, - langid = {english} + abstract = {We report the first tungsten isotopic measurements in stardust + silicon carbide (SiC) grains recovered from the Murchison + carbonaceous chondrite. The isotopes 182,183,184,186W and 179,180Hf + were measured on both an aggregate (KJB fraction) and single + stardust SiC grains (LS+LU fraction) believed to have condensed in + the outflows of low-mass carbon-rich asymptotic giant branch (AGB) + stars with close-to-solar metallicity. The SiC aggregate shows + small deviations from terrestrial (= solar) composition in the + 182W/184W and 183W/184W ratios, with deficits in 182W and 183W with + respect to 184W. The 186W/184W ratio, however, shows no apparent + deviation from the solar value. Tungsten isotopic measurements in + single mainstream stardust SiC grains revealed lower than solar + 182W/184W, 183W/184W, and 186W/184W ratios. We have compared the + SiC data with theoretical predictions of the evolution of W + isotopic ratios in the envelopes of AGB stars. These ratios are + affected by the slow neutron-capture process and match the SiC data + regarding their 182W/184W, 183W/184W, and 179Hf/180Hf isotopic + compositions, although a small adjustment in the s-process + production of 183W is needed in order to have a better agreement + between the SiC data and model predictions. The models cannot + explain the 186W/184W ratios observed in the SiC grains, even when + the current 185W neutron-capture cross section is increased by a + factor of two. Further study is required to better assess how model + uncertainties (e.g., the formation of the 13C neutron source, the + mass-loss law, the modeling of the third dredge-up, and the + efficiency of the 22Ne neutron source) may affect current s-process + predictions.}, + langid = {english}, } @article{barzykConstraining13CNeutron2007, - title = {Constraining the {\textsuperscript{13}}{{C}} Neutron Source in {{AGB}} Stars through Isotopic Analysis of Trace Elements in Presolar {{SiC}}}, - author = {Barzyk, J. G. and Savina, M. R. and Davis, A. M. and Gallino, R. and Gyngard, F. and Amari, S. and Zinner, E. and Pellin, M. J. and Lewis, R. S. and Clayton, R. N.}, - year = {2007}, + title = {Constraining the {$^{13}$}{{C}} Neutron Source in {{AGB}} Stars + through Isotopic Analysis of Trace Elements in Presolar {{SiC}}}, + author = {Barzyk, J. G. and Savina, M. R. and Davis, A. M. and Gallino, R. and + Gyngard, F. and Amari, S. and Zinner, E. and Pellin, M. J. and Lewis, + R. S. and Clayton, R. N.}, + year = 2007, journal = {Meteoritics \& Planetary Science}, volume = {42}, number = {7-8}, pages = {1103--1119}, publisher = {Wiley Online Library}, - doi = {10.1111/j.1945-5100.2007.tb00563.x} + doi = {10.1111/j.1945-5100.2007.tb00563.x}, } @article{Gra-1995-HOP-0, - title = {Isotopic Compositions of {{C}}, {{N}}, {{O}}, {{Mg}}, and {{Si}}, Trace Element Abundances, and Morphologies of Single Circumstellar Graphite Grains in Four Density Fractions from the {{Murchison}} Meteorite}, + title = {Isotopic Compositions of {{C}}, {{N}}, {{O}}, {{Mg}}, and {{Si}}, + Trace Element Abundances, and Morphologies of Single Circumstellar + Graphite Grains in Four Density Fractions from the {{Murchison}} + Meteorite}, author = {Hoppe, Peter and Amari, Sachiko and Zinner, Ernst and Lewis, Roy S.}, - year = {1995}, + year = 1995, month = oct, journal = {Geochimica et Cosmochimica Acta}, volume = {59}, @@ -40,15 +75,16 @@ @article{Gra-1995-HOP-0 issn = {00167037}, doi = {10.1016/0016-7037(95)00280-D}, urldate = {2024-07-10}, - copyright = {https://www.elsevier.com/tdm/userlicense/1.0/}, - langid = {english} + langid = {english}, } @article{Gra-1995-ZIN-0, - title = {Interstellar Graphite in Meteorites: {{Isotopic}} Compositions and Structural Properties of Single Graphite Grains from {{Murchison}}}, + title = {Interstellar Graphite in Meteorites: {{Isotopic}} Compositions and + Structural Properties of Single Graphite Grains from {{Murchison}}}, shorttitle = {Interstellar Graphite in Meteorites}, - author = {Zinner, Ernst and Amari, Sachiko and Wopenka, Brigitte and Lewis, Roy S.}, - year = {1995}, + author = {Zinner, Ernst and Amari, Sachiko and Wopenka, Brigitte and Lewis, + Roy S.}, + year = 1995, month = mar, journal = {Meteoritics}, volume = {30}, @@ -57,15 +93,58 @@ @article{Gra-1995-ZIN-0 issn = {0026-1114}, doi = {10.1111/j.1945-5100.1995.tb01115.x}, urldate = {2025-03-26}, - abstract = {Abstract--- One hundred forty-three carbon grains, ranging in size from 2 to 8 {$\mu$}m, from two chemical and physical separates from the Murchison CM2 chondrite, were analyzed by ion microprobe mass spectrometry for their C- and N-isotopic compositions. Both separates are enriched in the exotic noble gas component Ne-E(L). Ninety grains were also analyzed for their H and O contents and 118, for Si. Thirteen grains were analyzed by micro-sampling laser Raman spectroscopy. Round grains have large C-isotopic anomalies with 12 C/ 13 C ratios ranging from 7 to 4500 (terrestrial ratio = 89). Nitrogen in these grains is also anomalous but shows much smaller deviations from the terrestrial composition, 14 N/ 15 N ratios ranging from 193 to 680 (terrestrial ratio = 272). Spherulitic aggregates and non-round compact grains have normal C-isotopic ratios but 15 N excesses (up to 35\%). Raman spectra of the analyzed grains indicate varying degrees of crystalline disorder of graphite with estimated in-plane crystallite dimensions varying from 18 {\AA} (highly disordered, similar to terrestrial kerogen) to {$\sim$}750 {\AA} (well-crystallized graphite). Element contents of H, O, and Si are correlated with one another, and H and O are probably present in the form of organic molecules. On the basis of morphology, the round grains fall into two groups: grains with smooth, shell-like surfaces (``onions'') and grains that appear to be dense aggregates of small scales (``cauliflowers''). ``Onions'' tend to have lower trace element contents, isotopically light C ( 12 C/ 13 C {$>$} 89) and a high degree of crystalline order, whereas ``cauliflowers'' have a larger spread in trace element contents and C-isotopic ratios (they range from isotopically light to heavy) but tend to have a low degree of crystalline order. However, these differences exist only on average, and no clear distinction can be made for individual grains. A few limited conclusions can be drawn about the astrophysical origin of the carbon grains of this study. The 15 N excesses in spherulitic aggregates and non-round grains can be explained as the result of ion-molecule reactions in molecular clouds. The round grains, on the other hand, must have formed in stellar atmospheres (circumstellar grains). Grains with isotopically light C must have formed in stellar environments characterized by He-burning, either in the atmosphere of Wolf-Rayet stars during the WC phase or in the He-burning, 12 C-rich zone of a massive star, ejected by a supernova explosion. Isotopically heavy C is produced by H-burning in the CNO cycle. Possible sources for grains with heavy C are carbon stars (AGB stars during the thermally pulsing phase) or novae, but the detailed distribution of 12 C/ 13 C ratios agree neither with the distribution observed in carbon stars nor with theoretical predictions for these two types of stellar sources.}, - copyright = {http://onlinelibrary.wiley.com/termsAndConditions\#vor}, - langid = {english} + abstract = {Abstract--- One hundred forty-three carbon grains, ranging in size + from 2 to 8 {$\mu$}m, from two chemical and physical separates from + the Murchison CM2 chondrite, were analyzed by ion microprobe mass + spectrometry for their C- and N-isotopic compositions. Both + separates are enriched in the exotic noble gas component Ne-E(L). + Ninety grains were also analyzed for their H and O contents and 118 + , for Si. Thirteen grains were analyzed by micro-sampling laser + Raman spectroscopy. Round grains have large C-isotopic anomalies + with 12 C/ 13 C ratios ranging from 7 to 4500 (terrestrial ratio = + 89). Nitrogen in these grains is also anomalous but shows much + smaller deviations from the terrestrial composition, 14 N/ 15 N + ratios ranging from 193 to 680 (terrestrial ratio = 272). + Spherulitic aggregates and non-round compact grains have normal + C-isotopic ratios but 15 N excesses (up to 35\%). Raman spectra of + the analyzed grains indicate varying degrees of crystalline + disorder of graphite with estimated in-plane crystallite dimensions + varying from 18 \AA{} (highly disordered, similar to terrestrial + kerogen) to {$\sim$}750 \AA{} (well-crystallized graphite). Element + contents of H, O, and Si are correlated with one another, and H and + O are probably present in the form of organic molecules. On the + basis of morphology, the round grains fall into two groups: grains + with smooth, shell-like surfaces (``onions'') and grains that + appear to be dense aggregates of small scales (``cauliflowers''). + ``Onions'' tend to have lower trace element contents, isotopically + light C ( 12 C/ 13 C {$>$} 89) and a high degree of crystalline + order, whereas ``cauliflowers'' have a larger spread in trace + element contents and C-isotopic ratios (they range from + isotopically light to heavy) but tend to have a low degree of + crystalline order. However, these differences exist only on average + , and no clear distinction can be made for individual grains. A few + limited conclusions can be drawn about the astrophysical origin of + the carbon grains of this study. The 15 N excesses in spherulitic + aggregates and non-round grains can be explained as the result of + ion-molecule reactions in molecular clouds. The round grains, on + the other hand, must have formed in stellar atmospheres + (circumstellar grains). Grains with isotopically light C must have + formed in stellar environments characterized by He-burning, either + in the atmosphere of Wolf-Rayet stars during the WC phase or in the + He-burning, 12 C-rich zone of a massive star, ejected by a + supernova explosion. Isotopically heavy C is produced by H-burning + in the CNO cycle. Possible sources for grains with heavy C are + carbon stars (AGB stars during the thermally pulsing phase) or + novae, but the detailed distribution of 12 C/ 13 C ratios agree + neither with the distribution observed in carbon stars nor with + theoretical predictions for these two types of stellar sources.}, + langid = {english}, } @article{Gra-1996-AMA-0, - title = {{\textsuperscript{41}}{{Ca}} in Presolar Graphite of Supernova Origin}, + title = {{$^{41}$}{{Ca}} in Presolar Graphite of Supernova Origin}, author = {Amari, Sachiko and Zinner, Ernst and Lewis, Roy S.}, - year = {1996}, + year = 1996, month = oct, journal = {The Astrophysical Journal}, volume = {470}, @@ -73,14 +152,16 @@ @article{Gra-1996-AMA-0 pages = {L101-L104}, issn = {0004637X}, doi = {10.1086/310306}, - urldate = {2024-07-10} + urldate = {2024-07-10}, } @article{Gra-1996-NIT-0, - title = {Extinct {\textsuperscript{44}}{{Ti}} in Presolar Graphite and {{SiC}}: {{Proof}} of a Supernova Origin}, - shorttitle = {Extinct {\textsuperscript{44}} {{Ti}} in {{Presolar Graphite}} and {{SiC}}}, - author = {Nittler, Larry R. and Amari, Sachiko and Zinner, Ernst and Woosley, S. E. and Lewis, Roy S.}, - year = {1996}, + title = {Extinct {$^{44}$}{{Ti}} in Presolar Graphite and {{SiC}} : {{Proof}} + of a Supernova Origin}, + shorttitle = {Extinct {$^{44}$} {{Ti}} in {{Presolar Graphite}} and {{SiC}}}, + author = {Nittler, Larry R. and Amari, Sachiko and Zinner, Ernst and Woosley, + S. E. and Lewis, Roy S.}, + year = 1996, month = may, journal = {The Astrophysical Journal}, volume = {462}, @@ -88,14 +169,18 @@ @article{Gra-1996-NIT-0 pages = {L31-L34}, issn = {0004-637X, 1538-4357}, doi = {10.1088/1538-4357/462/1/L31}, - urldate = {2024-07-10} + urldate = {2024-07-10}, } @article{Gra-1998-NIC-0, - title = {Zirconium and Molybdenum in {{Individual}} Circumstellar Graphite Grains: {{New}} Isotopic Data on the Nucleosynthesis of Heavy Elements}, - shorttitle = {Zirconium and {{Molybdenum}} in {{Individual Circumstellar Graphite Grains}}}, - author = {Nicolussi, Gunther K. and Pellin, Michael J. and Lewis, Roy S. and Davis, Andrew M. and Clayton, Robert N. and Amari, Sachiko}, - year = {1998}, + title = {Zirconium and Molybdenum in {{Individual}} Circumstellar Graphite + Grains: {{New}} Isotopic Data on the Nucleosynthesis of Heavy Elements + }, + shorttitle = {Zirconium and {{Molybdenum}} in {{Individual Circumstellar + Graphite Grains}}}, + author = {Nicolussi, Gunther K. and Pellin, Michael J. and Lewis, Roy S. and + Davis, Andrew M. and Clayton, Robert N. and Amari, Sachiko}, + year = 1998, month = sep, journal = {The Astrophysical Journal}, volume = {504}, @@ -104,13 +189,14 @@ @article{Gra-1998-NIC-0 issn = {0004-637X, 1538-4357}, doi = {10.1086/306072}, urldate = {2024-07-10}, - langid = {english} + langid = {english}, } @article{Gra-1999-TRA-0, - title = {Low-density Graphite Grains and Mixing in Type {{II}} Supernovae}, - author = {Travaglio, Claudia and Gallino, Roberto and Amari, Sachiko and Zinner, Ernst and Woosley, Stan and Lewis, Roy S.}, - year = {1999}, + title = {Low-Density Graphite Grains and Mixing in Type {{II}} Supernovae}, + author = {Travaglio, Claudia and Gallino, Roberto and Amari, Sachiko and + Zinner, Ernst and Woosley, Stan and Lewis, Roy S.}, + year = 1999, month = jan, journal = {The Astrophysical Journal}, volume = {510}, @@ -119,13 +205,15 @@ @article{Gra-1999-TRA-0 issn = {0004-637X, 1538-4357}, doi = {10.1086/306551}, urldate = {2024-07-10}, - langid = {english} + langid = {english}, } @article{Gra-2003-CRO-0, - title = {Structural, Chemical, and Isotopic Microanalytical Investigations of Graphite from Supernovae}, - author = {Croat, T.Kevin and Bernatowicz, Thomas and Amari, Sachiko and Messenger, Scott and Stadermann, Frank J}, - year = {2003}, + title = {Structural, Chemical, and Isotopic Microanalytical Investigations of + Graphite from Supernovae}, + author = {Croat, T.Kevin and Bernatowicz, Thomas and Amari, Sachiko and + Messenger, Scott and Stadermann, Frank J}, + year = 2003, month = dec, journal = {Geochimica et Cosmochimica Acta}, volume = {67}, @@ -134,14 +222,14 @@ @article{Gra-2003-CRO-0 issn = {00167037}, doi = {10.1016/S0016-7037(03)00463-0}, urldate = {2024-07-10}, - copyright = {https://www.elsevier.com/tdm/userlicense/1.0/}, - langid = {english} + langid = {english}, } @article{Gra-2008-JAD-0, - title = {New Stellar Sources for High-density, Presolar Graphite Grains}, - author = {Jadhav, Manavi and Amari, Sachiko and Marhas, Kuljeet K. and Zinner, Ernst and Maruoka, Teruyuki and Gallino, Roberto}, - year = {2008}, + title = {New Stellar Sources for High-Density, Presolar Graphite Grains}, + author = {Jadhav, Manavi and Amari, Sachiko and Marhas, Kuljeet K. and Zinner, + Ernst and Maruoka, Teruyuki and Gallino, Roberto}, + year = 2008, month = aug, journal = {The Astrophysical Journal}, volume = {682}, @@ -150,13 +238,16 @@ @article{Gra-2008-JAD-0 issn = {0004-637X, 1538-4357}, doi = {10.1086/589139}, urldate = {2024-07-10}, - langid = {english} + langid = {english}, } @article{Gra-2009-HEC-0, - title = {Ne Isotopes in Individual Presolar Graphite Grains from the {{Murchison}} Meteorite Together with {{He}}, {{C}}, {{O}}, {{Mg-Al}} Isotopic Analyses as Tracers of Their Origins}, - author = {Heck, Philipp R. and Amari, Sachiko and Hoppe, Peter and Baur, Heinrich and Lewis, Roy S. and Wieler, Rainer}, - year = {2009}, + title = {Ne Isotopes in Individual Presolar Graphite Grains from the {{ + Murchison}} Meteorite Together with {{He}}, {{C}}, {{O}}, {{Mg-Al}} + Isotopic Analyses as Tracers of Their Origins}, + author = {Heck, Philipp R. and Amari, Sachiko and Hoppe, Peter and Baur, + Heinrich and Lewis, Roy S. and Wieler, Rainer}, + year = 2009, month = aug, journal = {The Astrophysical Journal}, volume = {701}, @@ -164,13 +255,14 @@ @article{Gra-2009-HEC-0 pages = {1415--1425}, issn = {0004-637X, 1538-4357}, doi = {10.1088/0004-637X/701/2/1415}, - urldate = {2024-07-10} + urldate = {2024-07-10}, } @article{Gra-2010-CRO-0, - title = {Unusual {\textsuperscript{29,30}}{{Si-rich SiCs}} of Massive Star Origin Found within Graphites from the {{Murchison}} Meteorite}, + title = {Unusual {\textsuperscript{29,30}}{{Si-rich SiCs}} of Massive Star + Origin Found within Graphites from the {{Murchison}} Meteorite}, author = {Croat, T. K. and Stadermann, F. J. and Bernatowicz, T. J.}, - year = {2010}, + year = 2010, month = jun, journal = {The Astronomical Journal}, volume = {139}, @@ -178,13 +270,14 @@ @article{Gra-2010-CRO-0 pages = {2159--2169}, issn = {0004-6256, 1538-3881}, doi = {10.1088/0004-6256/139/6/2159}, - urldate = {2025-03-26} + urldate = {2025-03-26}, } @article{Gra-2012-GRO-0, - title = {C, {{N}}, and {{O}} Isotopic Heterogeneities in Low-Density Supernova Graphite Grains from {{Orgeuil}}}, + title = {C, {{N}}, and {{O}} Isotopic Heterogeneities in Low-Density Supernova + Graphite Grains from {{Orgeuil}}}, author = {Groopman, Evan and Bernatowicz, Thomas and Zinner, Ernst}, - year = {2012}, + year = 2012, month = jul, journal = {The Astrophysical Journal}, volume = {754}, @@ -192,13 +285,16 @@ @article{Gra-2012-GRO-0 pages = {L8}, issn = {2041-8205, 2041-8213}, doi = {10.1088/2041-8205/754/1/L8}, - urldate = {2024-07-10} + urldate = {2024-07-10}, } @article{Gra-2012-MEI-0, - title = {Graphite Grains in Supernova Ejecta -- {{Insights}} from a Noble Gas Study of 91 Individual {{KFC1}} Presolar Graphite Grains from the {{Murchison}} Meteorite}, - author = {Meier, M.M.M. and Heck, P.R. and Amari, S. and Baur, H. and Wieler, R.}, - year = {2012}, + title = {Graphite Grains in Supernova Ejecta -- {{Insights}} from a Noble Gas + Study of 91 Individual {{KFC1}} Presolar Graphite Grains from the {{ + Murchison}} Meteorite}, + author = {Meier, M.M.M. and Heck, P.R. and Amari, S. and Baur, H. and Wieler, + R.}, + year = 2012, month = jan, journal = {Geochimica et Cosmochimica Acta}, volume = {76}, @@ -206,14 +302,15 @@ @article{Gra-2012-MEI-0 issn = {00167037}, doi = {10.1016/j.gca.2011.10.027}, urldate = {2024-07-10}, - copyright = {https://www.elsevier.com/tdm/userlicense/1.0/}, - langid = {english} + langid = {english}, } @article{Gra-2013-JAD-0, - title = {Multi-Element Isotopic Analyses of Presolar Graphite Grains from {{Orgueil}}}, - author = {Jadhav, Manavi and Zinner, Ernst and Amari, Sachiko and Maruoka, Teruyuki and Marhas, Kuljeet K. and Gallino, Roberto}, - year = {2013}, + title = {Multi-Element Isotopic Analyses of Presolar Graphite Grains from {{ + Orgueil}}}, + author = {Jadhav, Manavi and Zinner, Ernst and Amari, Sachiko and Maruoka, + Teruyuki and Marhas, Kuljeet K. and Gallino, Roberto}, + year = 2013, month = jul, journal = {Geochimica et Cosmochimica Acta}, volume = {113}, @@ -221,15 +318,15 @@ @article{Gra-2013-JAD-0 issn = {00167037}, doi = {10.1016/j.gca.2013.01.018}, urldate = {2024-07-10}, - copyright = {https://www.elsevier.com/tdm/userlicense/1.0/}, - langid = {english} + langid = {english}, } @article{Gra-2013-WOP-0, - title = {Murchison Presolar Carbon Grains of Different Density Fractions: {{A Raman}} Spectroscopic Perspective}, + title = {Murchison Presolar Carbon Grains of Different Density Fractions: {{A + Raman}} Spectroscopic Perspective}, shorttitle = {Murchison Presolar Carbon Grains of Different Density Fractions}, author = {Wopenka, B. and Xu, Y.C. and Zinner, E. and Amari, S.}, - year = {2013}, + year = 2013, month = apr, journal = {Geochimica et Cosmochimica Acta}, volume = {106}, @@ -237,15 +334,15 @@ @article{Gra-2013-WOP-0 issn = {00167037}, doi = {10.1016/j.gca.2012.12.022}, urldate = {2025-03-26}, - copyright = {https://www.elsevier.com/tdm/userlicense/1.0/}, - langid = {english} + langid = {english}, } @article{Gra-2014-AMA-0, - title = {Presolar Graphite from the {{Murchison}} Meteorite: {{An}} Isotopic Study}, + title = {Presolar Graphite from the {{Murchison}} Meteorite: {{An}} Isotopic + Study}, shorttitle = {Presolar Graphite from the {{Murchison}} Meteorite}, author = {Amari, Sachiko and Zinner, Ernst and Gallino, Roberto}, - year = {2014}, + year = 2014, month = may, journal = {Geochimica et Cosmochimica Acta}, volume = {133}, @@ -253,24 +350,29 @@ @article{Gra-2014-AMA-0 issn = {00167037}, doi = {10.1016/j.gca.2014.01.006}, urldate = {2024-07-10}, - copyright = {https://www.elsevier.com/tdm/userlicense/1.0/}, - langid = {english} + langid = {english}, } @article{Gra-2015-GRO-0, - title = {Correlated {{NanoSIMS}}, {{TEM}}, and {{XANES Studies}} of {{Presolar Grains}}}, + title = {Correlated {{NanoSIMS}}, {{TEM}}, and {{XANES Studies}} of {{Presolar + Grains}}}, author = {Groopman, Evan Edward}, - year = {2015}, + year = 2015, publisher = {Washington University in St. Louis}, doi = {10.7936/K7P26W8R}, - urldate = {2025-03-26} + urldate = {2025-03-26}, } @article{Gra-2016-HAE-0, - title = {Coordinated Analysis of Two Graphite Grains from the {{CO3}}.0 {{LAP}} 031117 Meteorite: {{First}} Identification of a {{CO}} Nova Graphite and a Presolar Iron Sulfide Subgrain}, - shorttitle = {{{COORDINATED ANALYSIS OF TWO GRAPHITE GRAINS FROM THE CO3}}.0 {{LAP}} 031117 {{METEORITE}}}, - author = {Haenecour, Pierre and Floss, Christine and Jos{\'e}, Jordi and Amari, Sachiko and Lodders, Katharina and Jadhav, Manavi and Wang, Alian and Gyngard, Frank}, - year = {2016}, + title = {Coordinated Analysis of Two Graphite Grains from the {{CO3}}.0 {{LAP} + } 031117 Meteorite: {{First}} Identification of a {{CO}} Nova Graphite + and a Presolar Iron Sulfide Subgrain}, + shorttitle = {{{COORDINATED ANALYSIS OF TWO GRAPHITE GRAINS FROM THE CO3}}.0 { + {LAP}} 031117 {{METEORITE}}}, + author = {Haenecour, Pierre and Floss, Christine and Jos{\'e}, Jordi and Amari + , Sachiko and Lodders, Katharina and Jadhav, Manavi and Wang, Alian + and Gyngard, Frank}, + year = 2016, month = jul, journal = {The Astrophysical Journal}, volume = {825}, @@ -279,13 +381,34 @@ @article{Gra-2016-HAE-0 issn = {0004-637X, 1538-4357}, doi = {10.3847/0004-637X/825/2/88}, urldate = {2024-07-10}, - abstract = {ABSTRACT Presolar grains constitute the remnants of stars that existed before the formation of the solar system. In addition to providing direct information on the materials from which the solar system formed, these grains provide ground-truth information for models of stellar evolution and nucleosynthesis. Here we report the in situ identification of two unique presolar graphite grains from the primitive meteorite LaPaz Icefield 031117. Based on these two graphite grains, we estimate a bulk presolar graphite abundance of ppm in this meteorite. One of the grains (LAP-141) is characterized by an enrichment in 12 C and depletions in 33,34 S, and contains a small iron sulfide subgrain, representing the first unambiguous identification of presolar iron sulfide. The other grain (LAP-149) is extremely 13 C-rich and 15 N-poor, with one of the lowest 12 C/ 13 C ratios observed among presolar grains. Comparison of its isotopic compositions with new stellar nucleosynthesis and dust condensation models indicates an origin in the ejecta of a low-mass CO nova. Grain LAP-149 is the first putative nova grain that quantitatively best matches nova model predictions, providing the first strong evidence for graphite condensation in nova ejecta. Our discovery confirms that CO nova graphite and presolar iron sulfide contributed to the original building blocks of the solar system.} + abstract = {ABSTRACT Presolar grains constitute the remnants of stars that + existed before the formation of the solar system. In addition to + providing direct information on the materials from which the solar + system formed, these grains provide ground-truth information for + models of stellar evolution and nucleosynthesis. Here we report the + in situ identification of two unique presolar graphite grains from + the primitive meteorite LaPaz Icefield 031117. Based on these two + graphite grains, we estimate a bulk presolar graphite abundance of + ppm in this meteorite. One of the grains (LAP-141) is characterized + by an enrichment in 12 C and depletions in 33,34 S, and contains a + small iron sulfide subgrain, representing the first unambiguous + identification of presolar iron sulfide. The other grain (LAP-149) + is extremely 13 C-rich and 15 N-poor, with one of the lowest 12 C/ + 13 C ratios observed among presolar grains. Comparison of its + isotopic compositions with new stellar nucleosynthesis and dust + condensation models indicates an origin in the ejecta of a low-mass + CO nova. Grain LAP-149 is the first putative nova grain that + quantitatively best matches nova model predictions, providing the + first strong evidence for graphite condensation in nova ejecta. Our + discovery confirms that CO nova graphite and presolar iron sulfide + contributed to the original building blocks of the solar system.}, } @article{Gra-2016-XUY-0, - title = {The First Discovery of Presolar Graphite Grains from the Highly Reducing {{Qingzhen}} ({{EH3}}) Meteorite}, + title = {The First Discovery of Presolar Graphite Grains from the Highly + Reducing {{Qingzhen}} ({{EH3}}) Meteorite}, author = {Xu, Yuchen and Lin, Yangting and Zhang, Jianchao and Hao, Jialong}, - year = {2016}, + year = 2016, month = jul, journal = {The Astrophysical Journal}, volume = {825}, @@ -294,13 +417,43 @@ @article{Gra-2016-XUY-0 issn = {0004-637X, 1538-4357}, doi = {10.3847/0004-637X/825/2/111}, urldate = {2025-03-26}, - abstract = {ABSTRACT Presolar graphite grains have been extensively studied, but are limited in carbonaceous chondrites, particularly in Murchison (CM2) and Orgueil (CI1), which sampled materials from the oxidizing regions in the solar nebula. Here, we report the first discovery of presolar graphite grains from the Qingzhen (EH3) enstatite chondrite which formed under a highly reducing condition. Eighteen presolar graphite grains were identified by C-isotope mapping of the low-density fraction (1.75--1.85 g cm -3 ) from Qingzhen acid residue. Another 58 graphite spherules were found in different areas of the same sample mount using a scanning electron microscope and were classified into three morphologies, including cauliflower, onion, and cauliflower--onion. The Raman spectra of these spherules vary from ordered, disordered, and glassy to kerogen-like, suggestive of a wide range of thermal metamorphisms. NanoSIMS analysis of the C- and Si-isotopes of these graphite spherules confirmed 23 presolar grains. The other 35 graphite spherules have no significant isotopic anomalies, but they share similar morphologies and Raman spectra with the presolar ones. Another three grains were identified during NanoSIMS analysis. Of all the 44 presolar graphite grains identified, six grains show 28 Si-excesses, suggestive of supernovae origins, and four grains are 12 C- and 29,30 Si-rich, consistent with low-metallicity asymptotic giant branch star origins. Another two graphite spherules have extremely low 12 C/ 13 C ratios with marginal solar Si-isotopes. The morphologies, Raman spectra, and C- and Si-isotopic distributions of the presolar graphite grains from the Qingzhen enstatite chondrite are similar to those of the low-density fractions from Murchison carbonaceous chondrites. This study suggests a homogeneous distribution of presolar graphite grains in the solar nebula.} + abstract = {ABSTRACT Presolar graphite grains have been extensively studied, + but are limited in carbonaceous chondrites, particularly in + Murchison (CM2) and Orgueil (CI1), which sampled materials from the + oxidizing regions in the solar nebula. Here, we report the first + discovery of presolar graphite grains from the Qingzhen (EH3) + enstatite chondrite which formed under a highly reducing condition. + Eighteen presolar graphite grains were identified by C-isotope + mapping of the low-density fraction (1.75--1.85 g cm -3 ) from + Qingzhen acid residue. Another 58 graphite spherules were found in + different areas of the same sample mount using a scanning electron + microscope and were classified into three morphologies, including + cauliflower, onion, and cauliflower--onion. The Raman spectra of + these spherules vary from ordered, disordered, and glassy to + kerogen-like, suggestive of a wide range of thermal metamorphisms. + NanoSIMS analysis of the C- and Si-isotopes of these graphite + spherules confirmed 23 presolar grains. The other 35 graphite + spherules have no significant isotopic anomalies, but they share + similar morphologies and Raman spectra with the presolar ones. + Another three grains were identified during NanoSIMS analysis. Of + all the 44 presolar graphite grains identified, six grains show 28 + Si-excesses, suggestive of supernovae origins, and four grains are + 12 C- and 29,30 Si-rich, consistent with low-metallicity asymptotic + giant branch star origins. Another two graphite spherules have + extremely low 12 C/ 13 C ratios with marginal solar Si-isotopes. + The morphologies, Raman spectra, and C- and Si-isotopic + distributions of the presolar graphite grains from the Qingzhen + enstatite chondrite are similar to those of the low-density + fractions from Murchison carbonaceous chondrites. This study + suggests a homogeneous distribution of presolar graphite grains in + the solar nebula.}, } @article{Gra-2018-GRO-0, - title = {Correlated {{XANES}}, {{TEM}}, and {{NanoSIMS}} of Presolar Graphite Grains}, + title = {Correlated {{XANES}}, {{TEM}}, and {{NanoSIMS}} of Presolar Graphite + Grains}, author = {Groopman, Evan E. and Nittler, Larry R.}, - year = {2018}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, volume = {221}, @@ -308,13 +461,17 @@ @article{Gra-2018-GRO-0 issn = {00167037}, doi = {10.1016/j.gca.2017.02.011}, urldate = {2025-03-26}, - langid = {english} + langid = {english}, } @article{Gra-2018-HEC-0, - title = {Neon Isotopes in Individual Presolar Low-density Graphite Grains from the {{Orgueil}} Meteorite}, - author = {Heck, Philipp R. and Jadhav, Manavi and Meier, Matthias M. M. and Maruoka, Teruyuki and Amari, Sachiko and Zinner, Ernst K. and Busemann, Henner and Maden, Colin and Gyngard, Frank and Baur, Heinrich and Wieler, Rainer}, - year = {2018}, + title = {Neon Isotopes in Individual Presolar Low-Density Graphite Grains from + the {{Orgueil}} Meteorite}, + author = {Heck, Philipp R. and Jadhav, Manavi and Meier, Matthias M. M. and + Maruoka, Teruyuki and Amari, Sachiko and Zinner, Ernst K. and + Busemann, Henner and Maden, Colin and Gyngard, Frank and Baur, + Heinrich and Wieler, Rainer}, + year = 2018, month = nov, journal = {Meteoritics \& Planetary Science}, volume = {53}, @@ -323,14 +480,79 @@ @article{Gra-2018-HEC-0 issn = {1086-9379, 1945-5100}, doi = {10.1111/maps.13129}, urldate = {2024-07-10}, - abstract = {Abstract We present He and Ne isotopes of individual presolar graphite grains from a low-density separate from Orgueil. Two grain mounts were analyzed with the same techniques but in a different sequence: The first one was measured with Nano SIMS followed by noble gas mass spectrometry, and the second one in reverse order. No grain contained 4 He and only one grain on the second mount contained 3 He. On the first mount, the grains had been extensively sputtered with Nano SIMS ion beams prior to noble gas analysis; we found only one grain out of 15 with presolar 22 Ne above detection limit. In contrast, we found presolar 22 Ne in six out of seven grains on the second mount that was not exposed to an ion beam prior to noble gas analysis. All 22 grains on the two mounts were imaged with scanning electron microscopy ( SEM ) and/or Auger microscopy. We present evidence that this contrasting observation is most likely due to e-beam--induced heating of the generally smaller grains on the first mount during SEM and Auger imaging, and not primarily due to the Nano SIMS analysis. If thermal contact of the grains to the substrate is absent, such that heat can only be dissipated via radiation, then the smaller, sputter-eroded grains are heated to higher temperatures such that noble gases can diffuse out. We discuss possible gas loss mechanisms and suggest solutions to reduce heating during e-beam analyses by minimizing voltages, beam currents, and dwell times. We also found small amounts of 21 Ne in five grains. Using isotope data we determined that the dominant sources of most grains are core-collapse supernovae, congruent with earlier studies of low-density presolar graphite from Murchison. Only two of the grains are most likely from AGB stars, and two others have an ambiguous origin.}, - langid = {english} + abstract = {Abstract We present He and Ne isotopes of individual presolar + graphite grains from a low-density separate from Orgueil. Two grain + mounts were analyzed with the same techniques but in a different + sequence: The first one was measured with Nano SIMS followed by + noble gas mass spectrometry, and the second one in reverse order. + No grain contained 4 He and only one grain on the second mount + contained 3 He. On the first mount, the grains had been extensively + sputtered with Nano SIMS ion beams prior to noble gas analysis; we + found only one grain out of 15 with presolar 22 Ne above detection + limit. In contrast, we found presolar 22 Ne in six out of seven + grains on the second mount that was not exposed to an ion beam + prior to noble gas analysis. All 22 grains on the two mounts were + imaged with scanning electron microscopy ( SEM ) and/or Auger + microscopy. We present evidence that this contrasting observation + is most likely due to e-beam--induced heating of the generally + smaller grains on the first mount during SEM and Auger imaging, and + not primarily due to the Nano SIMS analysis. If thermal contact of + the grains to the substrate is absent, such that heat can only be + dissipated via radiation, then the smaller, sputter-eroded grains + are heated to higher temperatures such that noble gases can diffuse + out. We discuss possible gas loss mechanisms and suggest solutions + to reduce heating during e-beam analyses by minimizing voltages, + beam currents, and dwell times. We also found small amounts of 21 + Ne in five grains. Using isotope data we determined that the + dominant sources of most grains are core-collapse supernovae, + congruent with earlier studies of low-density presolar graphite + from Murchison. Only two of the grains are most likely from AGB + stars, and two others have an ambiguous origin.}, + langid = {english}, } @article{Gra-2022-BAR-0, title = {Presolar Stardust in Asteroid {{Ryugu}}}, - author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and O'D. Alexander, Conel M. and De Gregorio, Bradley T. and Engrand, C{\'e}cile and Kebukawa, Yoko and Nagashima, Kazuhide and Stroud, Rhonda M. and Yabuta, Hikaru and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and Amari, Sachiko and Amelin, Yuri and Bajo, Ken-ichi and Bejach, Laure and Bizzarro, Martin and Bonal, Lydie and Bouvier, Audrey and Carlson, Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Cody, George D. and Dartois, Emmanuel and Dauphas, Nicolas and Davis, Andrew M. and Dazzi, Alexandre and {Deniset-Besseau}, Ariane and Di Rocco, Tommaso and Duprat, Jean and Fujiya, Wataru and Fukai, Ryota and Gautam, Ikshu and Haba, Makiko K. and Hashiguchi, Minako and Hibiya, Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter and Huss, Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and Ireland, Trevor R. and Ishikawa, Akira and Ito, Motoo and Itoh, Shoichi and Kamide, Kanami and Kawasaki, Noriyuki and David Kilcoyne, A. L. and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten and Komatani, Shintaro and Komatsu, Mutsumi and Krot, Alexander N. and Liu, Ming-Chang and Martins, Zita and Masuda, Yuki and Mathurin, J{\'e}r{\'e}mie and McKeegan, Kevin D. and Montagnac, Gilles and Morita, Mayu and Mostefaoui, Smail and Motomura, Kazuko and Moynier, Fr{\'e}d{\'e}ric and Nakai, Izumi and Nguyen, Ann N. and Ohigashi, Takuji and Okumura, Taiga and Onose, Morihiko and Pack, Andreas and Park, Changkun and Piani, Laurette and Qin, Liping and Quirico, Eric and Remusat, Laurent and Russell, Sara S. and Sakamoto, Naoya and Sandford, Scott A. and Sch{\"o}nb{\"a}chler, Maria and Shigenaka, Miho and Suga, Hiroki and Tafla, Lauren and Takahashi, Yoshio and Takeichi, Yasuo and Tamenori, Yusuke and Tang, Haolan and Terada, Kentaro and Terada, Yasuko and Usui, Tomohiro and {Verdier-Paoletti}, Maximilien and Wada, Sohei and Wadhwa, Meenakshi and Wakabayashi, Daisuke and Walker, Richard J. and Yamashita, Katsuyuki and Yamashita, Shohei and Yin, Qing-Zhu and Yokoyama, Tetsuya and Yoneda, Shigekazu and Young, Edward D. and Yui, Hiroharu and Zhang, Ai-Cheng and Abe, Masanao and Miyazaki, Akiko and Nakato, Aiko and Nakazawa, Satoru and Nishimura, Masahiro and Okada, Tatsuaki and Saiki, Takanao and Tanaka, Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, Sei-ichiro and Yada, Toru and Yogata, Kasumi and Yoshikawa, Makoto and Nakamura, Tomoki and Naraoka, Hiroshi and Noguchi, Takaaki and Okazaki, Ryuji and Sakamoto, Kanako and Tachibana, Shogo and Yurimoto, Hisayoshi}, - year = {2022}, + author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and O'D. + Alexander, Conel M. and De Gregorio, Bradley T. and cile Engrand, C{ + \'e} and Kebukawa, Yoko and Nagashima, Kazuhide and Stroud, Rhonda M. + and Yabuta, Hikaru and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me + and Amari, Sachiko and Amelin, Yuri and Bajo, Ken-ichi and Bejach, + Laure and Bizzarro, Martin and Bonal, Lydie and Bouvier, Audrey and + Carlson, Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Cody + , George D. and Dartois, Emmanuel and Dauphas, Nicolas and Davis, + Andrew M. and Dazzi, Alexandre and {Deniset-Besseau}, Ariane and Di + Rocco, Tommaso and Duprat, Jean and Fujiya, Wataru and Fukai, Ryota + and Gautam, Ikshu and Haba, Makiko K. and Hashiguchi, Minako and + Hibiya, Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter + and Huss, Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and + Ireland, Trevor R. and Ishikawa, Akira and Ito, Motoo and Itoh, + Shoichi and Kamide, Kanami and Kawasaki, Noriyuki and David Kilcoyne, + A. L. and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten + and Komatani, Shintaro and Komatsu, Mutsumi and Krot, Alexander N. + and Liu, Ming-Chang and Martins, Zita and Masuda, Yuki and Mathurin, + J{\'e}r{\'e}mie and McKeegan, Kevin D. and Montagnac, Gilles and + Morita, Mayu and Mostefaoui, Smail and Motomura, Kazuko and Moynier, + Fr{\'e}d{\'e}ric and Nakai, Izumi and Nguyen, Ann N. and Ohigashi, + Takuji and Okumura, Taiga and Onose, Morihiko and Pack, Andreas and + Park, Changkun and Piani, Laurette and Qin, Liping and Quirico, Eric + and Remusat, Laurent and Russell, Sara S. and Sakamoto, Naoya and + Sandford, Scott A. and Sch{\"o}nb{\"a}chler, Maria and Shigenaka, + Miho and Suga, Hiroki and Tafla, Lauren and Takahashi, Yoshio and + Takeichi, Yasuo and Tamenori, Yusuke and Tang, Haolan and Terada, + Kentaro and Terada, Yasuko and Usui, Tomohiro and {Verdier-Paoletti}, + Maximilien and Wada, Sohei and Wadhwa, Meenakshi and Wakabayashi, + Daisuke and Walker, Richard J. and Yamashita, Katsuyuki and Yamashita + , Shohei and Yin, Qing-Zhu and Yokoyama, Tetsuya and Yoneda, + Shigekazu and Young, Edward D. and Yui, Hiroharu and Zhang, Ai-Cheng + and Abe, Masanao and Miyazaki, Akiko and Nakato, Aiko and Nakazawa, + Satoru and Nishimura, Masahiro and Okada, Tatsuaki and Saiki, Takanao + and Tanaka, Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, + Sei-ichiro and Yada, Toru and Yogata, Kasumi and Yoshikawa, Makoto + and Nakamura, Tomoki and Naraoka, Hiroshi and Noguchi, Takaaki and + Okazaki, Ryuji and Sakamoto, Kanako and Tachibana, Shogo and Yurimoto + , Hisayoshi}, + year = 2022, month = aug, journal = {The Astrophysical Journal Letters}, volume = {935}, @@ -339,13 +561,41 @@ @article{Gra-2022-BAR-0 issn = {2041-8205, 2041-8213}, doi = {10.3847/2041-8213/ac83bd}, urldate = {2024-07-10}, - abstract = {Abstract We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8 - 2.6 + 4.7 ppm for O-anomalous grains, 25 - 5 + 6 ppm for SiC grains, and 11 - 3 + 5 ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of 15 SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23 - 6 + 7 ppm SiC and 9.0 - 3.6 + 5.4 ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu--CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material.} + abstract = {Abstract We have conducted a NanoSIMS-based search for presolar + material in samples recently returned from C-type asteroid Ryugu as + part of JAXA's Hayabusa2 mission. We report the detection of all + major presolar grain types with O- and C-anomalous isotopic + compositions typically identified in carbonaceous chondrite + meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of + ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two + of the carbonaceous grains are presolar graphites, whereas several + grains with moderate C isotopic anomalies are probably organics. + The presolar silicate was located in a clast with a less altered + lithology than the typical extensively aqueously altered Ryugu + matrix. The matrix-normalized presolar grain abundances in Ryugu + are 4.8 - 2.6 + 4.7 ppm for O-anomalous grains, 25 - 5 + 6 ppm for + SiC grains, and 11 - 3 + 5 ppm for carbonaceous grains. Ryugu is + isotopically and petrologically similar to carbonaceous Ivuna-type + (CI) chondrites. To compare the in situ presolar grain abundances + of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil + samples and found a total of 15 SiC grains and 6 carbonaceous + grains. No O-anomalous grains were detected. The matrix-normalized + presolar grain abundances in the CI chondrites are similar to those + in Ryugu: 23 - 6 + 7 ppm SiC and 9.0 - 3.6 + 5.4 ppm carbonaceous + grains. Thus, our results provide further evidence in support of + the Ryugu--CI connection. They also reveal intriguing hints of + small-scale heterogeneities in the Ryugu samples, such as locally + distinct degrees of alteration that allowed the preservation of + delicate presolar material.}, } @article{Gra-2022-BAR-1, - title = {Presolar {{O-}} and {{C-anomalous}} Grains in Unequilibrated Ordinary Chondrite Matrices}, - author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and Dobric{\u a}, Elena and Brearley, Adrian J. and Hezel, Dominik C. and Alexander, Conel M. O'D.}, - year = {2022}, + title = {Presolar {{O-}} and {{C-anomalous}} Grains in Unequilibrated Ordinary + Chondrite Matrices}, + author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and Dobric{\u + a}, Elena and Brearley, Adrian J. and Hezel, Dominik C. and Alexander + , Conel M. O'D.}, + year = 2022, month = oct, journal = {Geochimica et Cosmochimica Acta}, volume = {335}, @@ -353,13 +603,43 @@ @article{Gra-2022-BAR-1 issn = {00167037}, doi = {10.1016/j.gca.2022.08.027}, urldate = {2024-07-10}, - langid = {english} + langid = {english}, } @article{Gra-2022-ITO-0, - title = {A Pristine Record of Outer {{Solar System}} Materials from Asteroid {{Ryugu}}'s Returned Sample}, - author = {Ito, Motoo and Tomioka, Naotaka and Uesugi, Masayuki and Yamaguchi, Akira and Shirai, Naoki and Ohigashi, Takuji and Liu, Ming-Chang and Greenwood, Richard C. and Kimura, Makoto and Imae, Naoya and Uesugi, Kentaro and Nakato, Aiko and Yogata, Kasumi and Yuzawa, Hayato and Kodama, Yu and Tsuchiyama, Akira and Yasutake, Masahiro and Findlay, Ross and Franchi, Ian A. and Malley, James A. and McCain, Kaitlyn A. and Matsuda, Nozomi and McKeegan, Kevin D. and Hirahara, Kaori and Takeuchi, Akihisa and Sekimoto, Shun and Sakurai, Ikuya and Okada, Ikuo and Karouji, Yuzuru and Arakawa, Masahiko and Fujii, Atsushi and Fujimoto, Masaki and Hayakawa, Masahiko and Hirata, Naoyuki and Hirata, Naru and Honda, Rie and Honda, Chikatoshi and Hosoda, Satoshi and Iijima, Yu-ichi and Ikeda, Hitoshi and Ishiguro, Masateru and Ishihara, Yoshiaki and Iwata, Takahiro and Kawahara, Kosuke and Kikuchi, Shota and Kitazato, Kohei and Matsumoto, Koji and Matsuoka, Moe and Michikami, Tatsuhiro and Mimasu, Yuya and Miura, Akira and Mori, Osamu and Morota, Tomokatsu and Nakazawa, Satoru and Namiki, Noriyuki and Noda, Hirotomo and Noguchi, Rina and Ogawa, Naoko and Ogawa, Kazunori and Okada, Tatsuaki and Okamoto, Chisato and Ono, Go and Ozaki, Masanobu and Saiki, Takanao and Sakatani, Naoya and Sawada, Hirotaka and Senshu, Hiroki and Shimaki, Yuri and Shirai, Kei and Sugita, Seiji and Takei, Yuto and Takeuchi, Hiroshi and Tanaka, Satoshi and Tatsumi, Eri and Terui, Fuyuto and Tsukizaki, Ryudo and Wada, Koji and Yamada, Manabu and Yamada, Tetsuya and Yamamoto, Yukio and Yano, Hajime and Yokota, Yasuhiro and Yoshihara, Keisuke and Yoshikawa, Makoto and Yoshikawa, Kent and Fukai, Ryota and Furuya, Shizuho and Hatakeda, Kentaro and Hayashi, Tasuku and Hitomi, Yuya and Kumagai, Kazuya and Miyazaki, Akiko and Nishimura, Masahiro and Soejima, Hiromichi and Iwamae, Ayako and Yamamoto, Daiki and Yoshitake, Miwa and Yada, Toru and Abe, Masanao and Usui, Tomohiro and Watanabe, Sei-ichiro and Tsuda, Yuichi}, - year = {2022}, + title = {A Pristine Record of Outer {{Solar System}} Materials from Asteroid { + {Ryugu}}'s Returned Sample}, + author = {Ito, Motoo and Tomioka, Naotaka and Uesugi, Masayuki and Yamaguchi, + Akira and Shirai, Naoki and Ohigashi, Takuji and Liu, Ming-Chang and + Greenwood, Richard C. and Kimura, Makoto and Imae, Naoya and Uesugi, + Kentaro and Nakato, Aiko and Yogata, Kasumi and Yuzawa, Hayato and + Kodama, Yu and Tsuchiyama, Akira and Yasutake, Masahiro and Findlay, + Ross and Franchi, Ian A. and Malley, James A. and McCain, Kaitlyn A. + and Matsuda, Nozomi and McKeegan, Kevin D. and Hirahara, Kaori and + Takeuchi, Akihisa and Sekimoto, Shun and Sakurai, Ikuya and Okada, + Ikuo and Karouji, Yuzuru and Arakawa, Masahiko and Fujii, Atsushi and + Fujimoto, Masaki and Hayakawa, Masahiko and Hirata, Naoyuki and + Hirata, Naru and Honda, Rie and Honda, Chikatoshi and Hosoda, Satoshi + and Iijima, Yu-ichi and Ikeda, Hitoshi and Ishiguro, Masateru and + Ishihara, Yoshiaki and Iwata, Takahiro and Kawahara, Kosuke and + Kikuchi, Shota and Kitazato, Kohei and Matsumoto, Koji and Matsuoka, + Moe and Michikami, Tatsuhiro and Mimasu, Yuya and Miura, Akira and + Mori, Osamu and Morota, Tomokatsu and Nakazawa, Satoru and Namiki, + Noriyuki and Noda, Hirotomo and Noguchi, Rina and Ogawa, Naoko and + Ogawa, Kazunori and Okada, Tatsuaki and Okamoto, Chisato and Ono, Go + and Ozaki, Masanobu and Saiki, Takanao and Sakatani, Naoya and Sawada + , Hirotaka and Senshu, Hiroki and Shimaki, Yuri and Shirai, Kei and + Sugita, Seiji and Takei, Yuto and Takeuchi, Hiroshi and Tanaka, + Satoshi and Tatsumi, Eri and Terui, Fuyuto and Tsukizaki, Ryudo and + Wada, Koji and Yamada, Manabu and Yamada, Tetsuya and Yamamoto, Yukio + and Yano, Hajime and Yokota, Yasuhiro and Yoshihara, Keisuke and + Yoshikawa, Makoto and Yoshikawa, Kent and Fukai, Ryota and Furuya, + Shizuho and Hatakeda, Kentaro and Hayashi, Tasuku and Hitomi, Yuya + and Kumagai, Kazuya and Miyazaki, Akiko and Nishimura, Masahiro and + Soejima, Hiromichi and Iwamae, Ayako and Yamamoto, Daiki and + Yoshitake, Miwa and Yada, Toru and Abe, Masanao and Usui, Tomohiro + and Watanabe, Sei-ichiro and Tsuda, Yuichi}, + year = 2022, month = aug, journal = {Nature Astronomy}, volume = {6}, @@ -368,14 +648,61 @@ @article{Gra-2022-ITO-0 issn = {2397-3366}, doi = {10.1038/s41550-022-01745-5}, urldate = {2024-07-10}, - abstract = {Abstract Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth's water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment. Here we present the results of a detailed bulk and microanalytical study of pristine Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. Ryugu particles display a close compositional match with the chemically unfractionated, but aqueously altered, CI (Ivuna-type) chondrites, which are widely used as a proxy for the bulk Solar System composition. The sample shows an intricate spatial relationship between aliphatic-rich organics and phyllosilicates and indicates maximum temperatures of {\textasciitilde}30\,{$^\circ$}C during aqueous alteration. We find that heavy hydrogen and nitrogen abundances are consistent with an outer Solar System origin. Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition.}, - langid = {english} + abstract = {Abstract Volatile and organic-rich C-type asteroids may have been + one of the main sources of Earth's water. Our best insight into + their chemistry is currently provided by carbonaceous chondritic + meteorites, but the meteorite record is biased: only the strongest + types survive atmospheric entry and are then modified by + interaction with the terrestrial environment. Here we present the + results of a detailed bulk and microanalytical study of pristine + Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. + Ryugu particles display a close compositional match with the + chemically unfractionated, but aqueously altered, CI (Ivuna-type) + chondrites, which are widely used as a proxy for the bulk Solar + System composition. The sample shows an intricate spatial + relationship between aliphatic-rich organics and phyllosilicates + and indicates maximum temperatures of \textasciitilde 30\,{$^\circ$ + }C during aqueous alteration. We find that heavy hydrogen and + nitrogen abundances are consistent with an outer Solar System + origin. Ryugu particles are the most uncontaminated and + unfractionated extraterrestrial materials studied so far, and + provide the best available match to the bulk Solar System + composition.}, + langid = {english}, } @article{Gra-2023-NGU-0, - title = {Abundant Presolar Grains and Primordial Organics Preserved in Carbon-Rich Exogenous Clasts in Asteroid {{Ryugu}}}, - author = {Nguyen, Ann N. and Mane, Prajkta and Keller, Lindsay P. and Piani, Laurette and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and Alexander, Conel M. O'D. and Amari, Sachiko and Amelin, Yuri and Bajo, Ken-ichi and Bizzarro, Martin and Bouvier, Audrey and Carlson, Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Dauphas, Nicolas and Davis, Andrew M. and Di Rocco, Tommaso and Fujiya, Wataru and Fukai, Ryota and Gautam, Ikshu and Haba, Makiko K. and Hibiya, Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter and Huss, Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and Ireland, Trevor R. and Ishikawa, Akira and Itoh, Shoichi and Kawasaki, Noriyuki and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten and Komatani, Shintaro and Krot, Alexander N. and Liu, Ming-Chang and Masuda, Yuki and McKeegan, Kevin D. and Morita, Mayu and Motomura, Kazuko and Moynier, Fr{\'e}d{\'e}ric and Nakai, Izumi and Nagashima, Kazuhide and Nesvorn{\'y}, David and Nittler, Larry and Onose, Morihiko and Pack, Andreas and Park, Changkun and Qin, Liping and Russell, Sara S. and Sakamoto, Naoya and Sch{\"o}nb{\"a}chler, Maria and Tafla, Lauren and Tang, Haolan and Terada, Kentaro and Terada, Yasuko and Usui, Tomohiro and Wada, Sohei and Wadhwa, Meenakshi and Walker, Richard J. and Yamashita, Katsuyuki and Yin, Qing-Zhu and Yokoyama, Tetsuya and Yoneda, Shigekazu and Young, Edward D. and Yui, Hiroharu and Zhang, Ai-Cheng and Nakamura, Tomoki and Naraoka, Hiroshi and Noguchi, Takaaki and Okazaki, Ryuji and Sakamoto, Kanako and Yabuta, Hikaru and Abe, Masanao and Miyazaki, Akiko and Nakato, Aiko and Nishimura, Masahiro and Okada, Tatsuaki and Yada, Toru and Yogata, Kasumi and Nakazawa, Satoru and Saiki, Takanao and Tanaka, Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, Sei-ichiro and Yoshikawa, Makoto and Tachibana, Shogo and Yurimoto, Hisayoshi}, - year = {2023}, + title = {Abundant Presolar Grains and Primordial Organics Preserved in + Carbon-Rich Exogenous Clasts in Asteroid {{Ryugu}}}, + author = {Nguyen, Ann N. and Mane, Prajkta and Keller, Lindsay P. and Piani, + Laurette and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and + Alexander, Conel M. O'D. and Amari, Sachiko and Amelin, Yuri and Bajo + , Ken-ichi and Bizzarro, Martin and Bouvier, Audrey and Carlson, + Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Dauphas, + Nicolas and Davis, Andrew M. and Di Rocco, Tommaso and Fujiya, Wataru + and Fukai, Ryota and Gautam, Ikshu and Haba, Makiko K. and Hibiya, + Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter and Huss + , Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and Ireland, + Trevor R. and Ishikawa, Akira and Itoh, Shoichi and Kawasaki, + Noriyuki and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten + and Komatani, Shintaro and Krot, Alexander N. and Liu, Ming-Chang and + Masuda, Yuki and McKeegan, Kevin D. and Morita, Mayu and Motomura, + Kazuko and Moynier, Fr{\'e}d{\'e}ric and Nakai, Izumi and Nagashima, + Kazuhide and Nesvorn{\'y}, David and Nittler, Larry and Onose, + Morihiko and Pack, Andreas and Park, Changkun and Qin, Liping and + Russell, Sara S. and Sakamoto, Naoya and Sch{\"o}nb{\"a}chler, Maria + and Tafla, Lauren and Tang, Haolan and Terada, Kentaro and Terada, + Yasuko and Usui, Tomohiro and Wada, Sohei and Wadhwa, Meenakshi and + Walker, Richard J. and Yamashita, Katsuyuki and Yin, Qing-Zhu and + Yokoyama, Tetsuya and Yoneda, Shigekazu and Young, Edward D. and Yui, + Hiroharu and Zhang, Ai-Cheng and Nakamura, Tomoki and Naraoka, + Hiroshi and Noguchi, Takaaki and Okazaki, Ryuji and Sakamoto, Kanako + and Yabuta, Hikaru and Abe, Masanao and Miyazaki, Akiko and Nakato, + Aiko and Nishimura, Masahiro and Okada, Tatsuaki and Yada, Toru and + Yogata, Kasumi and Nakazawa, Satoru and Saiki, Takanao and Tanaka, + Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, Sei-ichiro + and Yoshikawa, Makoto and Tachibana, Shogo and Yurimoto, Hisayoshi}, + year = 2023, month = jul, journal = {Science Advances}, volume = {9}, @@ -384,26 +711,49 @@ @article{Gra-2023-NGU-0 issn = {2375-2548}, doi = {10.1126/sciadv.adh1003}, urldate = {2024-07-10}, - abstract = {Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC ({\textasciitilde}235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2\%), and organics with C isotopic anomalies (0.2\%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugu's rubble pile origin. , Exogenic primitive clasts in Ryugu samples have remarkable abundances of presolar grains and isotopically anomalous organics.}, - langid = {english} + abstract = {Preliminary analyses of asteroid Ryugu samples show kinship to + aqueously altered CI (Ivuna-type) chondrites, suggesting similar + origins. We report identification of C-rich, particularly primitive + clasts in Ryugu samples that contain preserved presolar silicate + grains and exceptional abundances of presolar SiC and isotopically + anomalous organic matter. The high presolar silicate abundance (104 + ppm) indicates that the clast escaped extensive alteration. The 5 + to 10 times higher abundances of presolar SiC (\textasciitilde 235 + ppm), N-rich organic matter, organics with N isotopic anomalies + (1.2\%), and organics with C isotopic anomalies (0.2\%) in the + primitive clasts compared to bulk Ryugu suggest that the clasts + formed in a unique part of the protoplanetary disk enriched in + presolar materials. These clasts likely represent previously + unsampled outer solar system material that accreted onto Ryugu + after aqueous alteration ceased, consistent with Ryugu's rubble + pile origin. , Exogenic primitive clasts in Ryugu samples have + remarkable abundances of presolar grains and isotopically anomalous + organics.}, + langid = {english}, } @inproceedings{gyngardLithiumBoronSulphur2007, - title = {Lithium, {{Boron}}, and {{Sulphur Isotopic Ratios}} in {{Large Presolar SiC Grains}} from {{Murchison}}}, + title = {Lithium, {{Boron}}, and {{Sulphur Isotopic Ratios}} in {{Large + Presolar SiC Grains}} from {{Murchison}}}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Gyngard, F. and Amari, S. and Zinner, E. and Gallino, R. and Lewis, R. S.}, - year = {2007}, + author = {Gyngard, F. and Amari, S. and Zinner, E. and Gallino, R. and Lewis, + R. S.}, + year = 2007, volume = {38}, pages = {1963}, urldate = {2023-02-10}, - abstract = {We report here Li, B, and S isotopic ratios in nine large, up to 60 {$\mu$}m, presolar SiC grains from the Murchison L series.}, - annotation = {ADS Bibcode: 2007LPI....38.1963G} + abstract = {We report here Li, B, and S isotopic ratios in nine large, up to + 60 {$\mu$}m, presolar SiC grains from the Murchison L series.}, } @article{heckLifetimesInterstellarDust2020, - title = {Lifetimes of Interstellar Dust from Cosmic Ray Exposure Ages of Presolar Silicon Carbide}, - author = {Heck, Philipp R. and Greer, Jennika and K{\"o}{\"o}p, Levke and Trappitsch, Reto and Gyngard, Frank and Busemann, Henner and Maden, Colin and {\'A}vila, Jana{\'i}na N. and Davis, Andrew M. and Wieler, Rainer}, - year = {2020}, + title = {Lifetimes of Interstellar Dust from Cosmic Ray Exposure Ages of + Presolar Silicon Carbide}, + author = {Heck, Philipp R. and Greer, Jennika and K{\"o}{\"o}p, Levke and + Trappitsch, Reto and Gyngard, Frank and Busemann, Henner and Maden, + Colin and {\'A}vila, Jana{\'i}na N. and Davis, Andrew M. and Wieler, + Rainer}, + year = 2020, month = jan, journal = {Proceedings of the National Academy of Sciences}, volume = {117}, @@ -412,13 +762,32 @@ @article{heckLifetimesInterstellarDust2020 publisher = {Proceedings of the National Academy of Sciences}, doi = {10.1073/pnas.1904573117}, urldate = {2023-02-15}, - abstract = {We determined interstellar cosmic ray exposure ages of 40 large presolar silicon carbide grains extracted from the Murchison CM2 meteorite. Our ages, based on cosmogenic Ne-21, range from 3.9 {\textpm} 1.6 Ma to {$\sim$}3 {\textpm} 2 Ga before the start of the Solar System {$\sim$}4.6 Ga ago. A majority of the grains have interstellar lifetimes of {$<$}300 Ma, which is shorter than theoretical estimates for large grains. These grains condensed in outflows of asymptotic giant branch stars {$<$}4.9 Ga ago that possibly formed during an episode of enhanced star formation {$\sim$}7 Ga ago. A minority of the grains have ages {$>$}1 Ga. Longer lifetimes are expected for large grains. We determined that at least 12 of the analyzed grains were parts of aggregates in the interstellar medium: The large difference in nuclear recoil loss of cosmic ray spallation products 3He and 21Ne enabled us to estimate that the irradiated objects in the interstellar medium were up to 30 times larger than the analyzed grains. Furthermore, we estimate that the majority of the grains acquired the bulk of their cosmogenic nuclides in the interstellar medium and not by exposure to an enhanced particle flux of the early active sun.} + abstract = {We determined interstellar cosmic ray exposure ages of 40 large + presolar silicon carbide grains extracted from the Murchison CM2 + meteorite. Our ages, based on cosmogenic Ne-21, range from 3.9 + \textpm{} 1.6 Ma to {$\sim$}3 \textpm{} 2 Ga before the start of + the Solar System {$\sim$}4.6 Ga ago. A majority of the grains have + interstellar lifetimes of {$<$}300 Ma, which is shorter than + theoretical estimates for large grains. These grains condensed in + outflows of asymptotic giant branch stars {$<$}4.9 Ga ago that + possibly formed during an episode of enhanced star formation {$\sim + $}7 Ga ago. A minority of the grains have ages {$>$}1 Ga. Longer + lifetimes are expected for large grains. We determined that at + least 12 of the analyzed grains were parts of aggregates in the + interstellar medium: The large difference in nuclear recoil loss of + cosmic ray spallation products 3He and 21Ne enabled us to estimate + that the irradiated objects in the interstellar medium were up to + 30 times larger than the analyzed grains. Furthermore, we estimate + that the majority of the grains acquired the bulk of their + cosmogenic nuclides in the interstellar medium and not by exposure + to an enhanced particle flux of the early active sun.}, } @article{hoppeEvidenceExtinctVanadium492002, - title = {Evidence for Extinct Vanadium-49 in Presolar Silicon Carbide Grains from Supernovae}, + title = {Evidence for Extinct Vanadium-49 in Presolar Silicon Carbide Grains + from Supernovae}, author = {Hoppe, P. and Besmehn, A.}, - year = {2002}, + year = 2002, month = aug, journal = {The Astrophysical Journal}, volume = {576}, @@ -427,15 +796,31 @@ @article{hoppeEvidenceExtinctVanadium492002 issn = {0004-637X}, doi = {10.1086/342785}, urldate = {2023-01-27}, - abstract = {We report Si, Ca, and Ti-V isotopic data for seven presolar silicon carbide grains of type X separated from the Murchison CM2 meteorite. The silicon carbide X grains most likely formed in the ejecta of Type II supernova explosions as indicated by large isotopic anomalies. The X grains of this study have 29Si/28Si and 30Si/28Si ratios of 0.56-0.75 and 0.41-0.62 times the solar value, respectively. Slight enrichments in 44Ca are observed, possibly due to the decay of radioactive 44Ti (t1/2 = 60 yr). While 46Ti/48Ti, 47Ti/48Ti, and 50Ti/48Ti ratios are close to solar, all X grains have enhanced 49Ti/48Ti ratios of up to 1.9 times the solar ratio. The 49Ti/48Ti ratios are positively correlated with 51V/48Ti ratios, suggestive of the incorporation of live 49V (t1/2 = 330 days) during silicon carbide condensation. This implies that the grains formed on a timescale of several months after supernova explosion.}, - langid = {english} + abstract = {We report Si, Ca, and Ti-V isotopic data for seven presolar + silicon carbide grains of type X separated from the Murchison CM2 + meteorite. The silicon carbide X grains most likely formed in the + ejecta of Type II supernova explosions as indicated by large + isotopic anomalies. The X grains of this study have 29Si/28Si and + 30Si/28Si ratios of 0.56-0.75 and 0.41-0.62 times the solar value, + respectively. Slight enrichments in 44Ca are observed, possibly due + to the decay of radioactive 44Ti (t1/2 = 60 yr). While 46Ti/48Ti, + 47Ti/48Ti, and 50Ti/48Ti ratios are close to solar, all X grains + have enhanced 49Ti/48Ti ratios of up to 1.9 times the solar ratio. + The 49Ti/48Ti ratios are positively correlated with 51V/48Ti ratios + , suggestive of the incorporation of live 49V (t1/2 = 330 days) + during silicon carbide condensation. This implies that the grains + formed on a timescale of several months after supernova explosion.}, + langid = {english}, } @article{hussTitaniumIsotopicCompositions2007, - title = {Titanium Isotopic Compositions of Well-Characterized Silicon Carbide Grains from {{Orgueil}} ({{CI}}): {{Implications}} for s-Process Nucleosynthesis}, - shorttitle = {Titanium Isotopic Compositions of Well-Characterized Silicon Carbide Grains from {{Orgueil}} ({{CI}})}, + title = {Titanium Isotopic Compositions of Well-Characterized Silicon Carbide + Grains from {{Orgueil}} ({{CI}}): {{Implications}} for s-{{Process}} + Nucleosynthesis}, + shorttitle = {Titanium Isotopic Compositions of Well-Characterized Silicon + Carbide Grains from {{Orgueil}} ({{CI}})}, author = {Huss, Gary R. and Smith, Julie B.}, - year = {2007}, + year = 2007, journal = {Meteoritics \& Planetary Science}, volume = {42}, number = {7-8}, @@ -443,39 +828,73 @@ @article{hussTitaniumIsotopicCompositions2007 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2007.tb00561.x}, urldate = {2023-01-27}, - abstract = {Abstract--- We have measured the titanium isotopic compositions of 23 silicon carbide grains from the Orgueil (CI) carbonaceous chondrites for which isotopic compositions of silicon, carbon, and nitrogen and aluminum-magnesium systematics had been measured previously. Using the 16 most-precise measurements, we estimate the relative contributions of stellar nucleosynthesis during the asymptotic giant branch (AGB) phase and the initial compositions of the parent stars to the compositions of the grains. To do this, we compare our data to the results of several published stellar models that employ different values for some important parameters. Our analysis confirms that s-process synthesis during the AGB phase only slightly modified the titanium compositions in the envelopes of the stars where mainstream silicon carbide grains formed, as it did for silicon. Our analysis suggests that the parent stars of the {$>$}1 {$\mu$}m silicon carbide grains that we measured were generally somewhat more massive than the Sun (2--3 M{$\odot$}) and had metallicities similar to or slightly higher than solar. Here we differ slightly from results of previous studies, which indicated masses at the lower end of the range 1.5--3 M{$\odot$} and metallicities near solar. We also conclude that models using a standard 13C pocket, which produces a good match for the main component of s-process elements in the solar system, overestimate the contribution of the 13C pocket to s-process nucleosynthesis of titanium found in silicon carbide grains. Although previous studies have suggested that the solar system has a significantly different titanium isotopic composition than the parent stars of silicon carbide grains, we find no compelling evidence that the Sun falls off of the array defined by those stars. We also conclude that the Sun does lie on the low-metallicity end of the silicon and titanium arrays defined by mainstream silicon carbide grains.}, - langid = {english} + abstract = {Abstract--- We have measured the titanium isotopic compositions of + 23 silicon carbide grains from the Orgueil (CI) carbonaceous + chondrites for which isotopic compositions of silicon, carbon, and + nitrogen and aluminum-magnesium systematics had been measured + previously. Using the 16 most-precise measurements, we estimate the + relative contributions of stellar nucleosynthesis during the + asymptotic giant branch (AGB) phase and the initial compositions of + the parent stars to the compositions of the grains. To do this, we + compare our data to the results of several published stellar models + that employ different values for some important parameters. Our + analysis confirms that s-process synthesis during the AGB phase + only slightly modified the titanium compositions in the envelopes + of the stars where mainstream silicon carbide grains formed, as it + did for silicon. Our analysis suggests that the parent stars of the + {$>$}1 {$\mu$}m silicon carbide grains that we measured were + generally somewhat more massive than the Sun (2--3 M{$\odot$}) and + had metallicities similar to or slightly higher than solar. Here we + differ slightly from results of previous studies, which indicated + masses at the lower end of the range 1.5--3 M{$\odot$} and + metallicities near solar. We also conclude that models using a + standard 13C pocket, which produces a good match for the main + component of s-process elements in the solar system, overestimate + the contribution of the 13C pocket to s-process nucleosynthesis of + titanium found in silicon carbide grains. Although previous studies + have suggested that the solar system has a significantly different + titanium isotopic composition than the parent stars of silicon + carbide grains, we find no compelling evidence that the Sun falls + off of the array defined by those stars. We also conclude that the + Sun does lie on the low-metallicity end of the silicon and titanium + arrays defined by mainstream silicon carbide grains.}, + langid = {english}, } @article{linIsotopicAnalysisSupernova2010, - title = {Isotopic Analysis of Supernova {{SiC}} and {{Si3N4}} Grains from the {{Qingzhen}} ({{EH3}}) Chondrite}, + title = {Isotopic Analysis of Supernova {{SiC}} and {{Si3N4}} Grains from the + {{Qingzhen}} ({{EH3}}) Chondrite}, author = {Lin, Yangting and Gyngard, Frank and Zinner, Ernst}, - year = {2010}, + year = 2010, journal = {The Astrophysical Journal}, volume = {709}, number = {2}, pages = {1157}, publisher = {IOP Publishing}, - doi = {10.1088/0004-637X/709/2/1157} + doi = {10.1088/0004-637X/709/2/1157}, } @inproceedings{pellinCompleteIsotopicAnalysis2000, - title = {Toward Complete Isotopic Analysis of Individual Presolar Silicon Carbide Grains: {{C}}, {{N}}, {{Si}}, {{Sr}}, {{Zr}}, {{Mo}}, and {{Ba}} in Single Grains of Type {{X}}}, - shorttitle = {Toward {{Complete Isotopic Analysis}} of {{Individual Presolar Silicon Carbide Grains}}}, + title = {Toward Complete Isotopic Analysis of Individual Presolar Silicon + Carbide Grains: {{C}}, {{N}}, {{Si}}, {{Sr}}, {{Zr}}, {{Mo}}, and {{Ba + }} in Single Grains of Type {{X}}}, + shorttitle = {Toward {{Complete Isotopic Analysis}} of {{Individual Presolar + Silicon Carbide Grains}}}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Pellin, M. J. and Calaway, W. F. and Davis, A. M. and Lewis, R. S. and Amari, S. and Clayton, R. N.}, - year = {2000}, + author = {Pellin, M. J. and Calaway, W. F. and Davis, A. M. and Lewis, R. S. + and Amari, S. and Clayton, R. N.}, + year = 2000, month = mar, volume = {31}, pages = {1917}, urldate = {2023-01-30}, - annotation = {ADS Bibcode: 2000LPI....31.1917P} } @article{SiC-1992-AMA-0, - title = {Interstellar {{SiC}} with Unusual Isotopic Compositions - {{Grains}} from a Supernova?}, + title = {Interstellar {{SiC}} with Unusual Isotopic Compositions - {{Grains}} + from a Supernova?}, author = {Amari, Sachiko and Hoppe, Peter and Zinner, Ernst and Lewis, Roy S.}, - year = {1992}, + year = 1992, month = aug, journal = {The Astrophysical Journal}, volume = {394}, @@ -483,13 +902,15 @@ @article{SiC-1992-AMA-0 issn = {0004-637X, 1538-4357}, doi = {10.1086/186468}, urldate = {2023-01-23}, - langid = {english} + langid = {english}, } @article{SiC-1992-VIR-0, - title = {Isotopic, Optical, and Trace Element Properties of Large Single {{SiC}} Grains from the {{Murchison}} Meteorite}, - author = {Virag, Alois and Wopenka, Brigitte and Amari, Sachiko and Zinner, Ernst and Anders, Edward and Lewis, Roy S}, - year = {1992}, + title = {Isotopic, Optical, and Trace Element Properties of Large Single {{SiC + }} Grains from the {{Murchison}} Meteorite}, + author = {Virag, Alois and Wopenka, Brigitte and Amari, Sachiko and Zinner, + Ernst and Anders, Edward and Lewis, Roy S}, + year = 1992, month = apr, journal = {Geochimica et Cosmochimica Acta}, volume = {56}, @@ -498,15 +919,49 @@ @article{SiC-1992-VIR-0 issn = {0016-7037}, doi = {10.1016/0016-7037(92)90237-D}, urldate = {2023-01-26}, - abstract = {Forty-one large SiC grains from the Murchison CM2 chondrite, ranging up to 15 {\texttimes} 26 {$\mu$}m, were analyzed by ion probe mass spectrometry for the isotopic compositions of C, N, Mg, and Si, and the concentrations of Al, Ti, V, Fe, Zr, and Ba. Most grains were also examined by Raman spectroscopy. The majority have large isotopic anomalies, with 13C12C and 14N15N up to 30X and 9X solar, and 29,30Si enriched by up to 102\%.. Only two grains, characterized by extremely heavy carbon ({$\delta$}13C = 28,582 and 18,883\%.) give evidence for fossil 26Mg, with (26Al27Al)0 ratios of 2.1 {\texttimes} 10-3 and 3.9 {\texttimes} 10-3. On the basis of C and Si isotopic composition, twenty-nine of the grains fall into three compact clusters, presumably from three discrete sources. Two of these clusters are anomalous and comprise only grains of cubic structure (according to their Raman spectra). The third, isotopically, normal cluster contains only anhedral, noncubic grains; and although contamination cannot be categorically excluded, an origin in a reducing environment in the early solar system is a viable possibility. The reality of these clusters is further supported by differences in morphology, size, N-content, and Al/N. This clustering of coarsegrained ({$>$}6 {$\mu$}m) SiC stands in sharp contrast to the quasicontinuous distribution af finer grained SiC and suggests that the top {\textasciitilde} 0.1\% of the mass distribution is a distinct population. A few conclusions can be reached about the astrophysical origin of the coarse-grained SiC. The C and N isotopic compositions of the anomalous grains are not very diagnostic, being consistent with H-burning in the CNO cycle. The very existence of SiC requires C-rich stars, of C/O {$>$} 1. The Si-isotopic compositions qualitatively show the signature of neutron capture in He-burning shells of highly evolved stars, narrowing the choice to asymptotic giant branch (AGB) or Wolf-Rayet stars. AGB stars are the more likely candidates, as only they can (during their final, planetary nebula phase) provide high mass loss rates and hence the high gas densities required for growth of large SiC grains.}, - langid = {english} + abstract = {Forty-one large SiC grains from the Murchison CM2 chondrite, + ranging up to 15 \texttimes{} 26 {$\mu$}m, were analyzed by ion + probe mass spectrometry for the isotopic compositions of C, N, Mg, + and Si, and the concentrations of Al, Ti, V, Fe, Zr, and Ba. Most + grains were also examined by Raman spectroscopy. The majority have + large isotopic anomalies, with 13C12C and 14N15N up to 30X and 9X + solar, and 29,30Si enriched by up to 102\%.. Only two grains, + characterized by extremely heavy carbon ({$\delta$}13C = 28,582 and + 18,883\%.) give evidence for fossil 26Mg, with (26Al27Al)0 ratios + of 2.1 \texttimes{} 10-3 and 3.9 \texttimes{} 10-3. On the basis of + C and Si isotopic composition, twenty-nine of the grains fall into + three compact clusters, presumably from three discrete sources. Two + of these clusters are anomalous and comprise only grains of cubic + structure (according to their Raman spectra). The third, + isotopically, normal cluster contains only anhedral, noncubic + grains; and although contamination cannot be categorically excluded + , an origin in a reducing environment in the early solar system is + a viable possibility. The reality of these clusters is further + supported by differences in morphology, size, N-content, and Al/N. + This clustering of coarsegrained ({$>$}6 {$\mu$}m) SiC stands in + sharp contrast to the quasicontinuous distribution af finer grained + SiC and suggests that the top \textasciitilde{} 0.1\% of the mass + distribution is a distinct population. A few conclusions can be + reached about the astrophysical origin of the coarse-grained SiC. + The C and N isotopic compositions of the anomalous grains are not + very diagnostic, being consistent with H-burning in the CNO cycle. + The very existence of SiC requires C-rich stars, of C/O {$>$} 1. + The Si-isotopic compositions qualitatively show the signature of + neutron capture in He-burning shells of highly evolved stars, + narrowing the choice to asymptotic giant branch (AGB) or Wolf-Rayet + stars. AGB stars are the more likely candidates, as only they can + (during their final, planetary nebula phase) provide high mass loss + rates and hence the high gas densities required for growth of large + SiC grains.}, + langid = {english}, } @article{SiC-1993-ALE-0, - title = {Presolar {{SiC}} in Chondrites: {{How}} Variable and How Many Sources?}, + title = {Presolar {{SiC}} in Chondrites: {{How}} Variable and How Many + Sources?}, shorttitle = {Presolar {{SiC}} in Chondrites}, author = {Alexander, C. M. O'D., C. M}, - year = {1993}, + year = 1993, month = jun, journal = {Geochimica et Cosmochimica Acta}, volume = {57}, @@ -515,14 +970,50 @@ @article{SiC-1993-ALE-0 issn = {0016-7037}, doi = {10.1016/0016-7037(93)90395-D}, urldate = {2023-01-26}, - abstract = {The carbon and silicon isotopic compositions of 246 isotopically anomalous SiC grains found in relatively low concentration acid residues prepared from nine chondrites are reported. However, two of these residues, from Leoville (CV3) and Qingzhen (EH3), only produced one anomalous SiC grain each. The other meteorites studied included Murchison and six UOCs. The results for Murchison are broadly similar to those found by previous Murchison SiC studies. However, no two Murchison studies are identical, implying that despite the number of grains analyzed to date, we still do not have a representative sample of Murchison SiC. Statistical comparisons between the SiC in Murchison and other meteorites are also hampered by the small sample sizes relative to the range of isotopic compositions observed. Nevertheless, of the six UOCs studied only the results obtained from Inman are clearly different from Murchison. Several previous studies have concluded that most of the SiC formed in AGB stars, although the silicon isotopes remain problematic. However, few, if any, C-rich AGB stars have 12C13C ratios less than 20. Those SiC grains with the isotopically heaviest carbon (12C13C {$<$} 20) may have come from s-process poor J- and R-type carbon stars. Four small groups of grains, which appear to require a minimum of four distinct SiC sources, have been identified in a compilation of 308 individual SiC analyses but the overall lack of groupings in the compilation suggest that either there were a large number of stellar sources or that there were a few sources whose isotopic compositions varied considerably. Simple calculations suggest that one could expect 10 to 100 AGB stars to have contributed SiC to a protosolar system embedded in a mature molecular cloud. Even a few 10s of sources are enough to explain the apparent differences seen in the various studies of Murchison SiC and, with the exception of Inman, the differences observed from meteorite to meteorite. This number of sources would also appear to favor galactic chemical evolution as the explanation of the slope 1.3 array formed by SiC in silicon three isotope plots rather than explanations which appeal to a single star or rare high mass AGB stars.}, - langid = {english} + abstract = {The carbon and silicon isotopic compositions of 246 isotopically + anomalous SiC grains found in relatively low concentration acid + residues prepared from nine chondrites are reported. However, two + of these residues, from Leoville (CV3) and Qingzhen (EH3), only + produced one anomalous SiC grain each. The other meteorites studied + included Murchison and six UOCs. The results for Murchison are + broadly similar to those found by previous Murchison SiC studies. + However, no two Murchison studies are identical, implying that + despite the number of grains analyzed to date, we still do not have + a representative sample of Murchison SiC. Statistical comparisons + between the SiC in Murchison and other meteorites are also hampered + by the small sample sizes relative to the range of isotopic + compositions observed. Nevertheless, of the six UOCs studied only + the results obtained from Inman are clearly different from + Murchison. Several previous studies have concluded that most of the + SiC formed in AGB stars, although the silicon isotopes remain + problematic. However, few, if any, C-rich AGB stars have 12C13C + ratios less than 20. Those SiC grains with the isotopically + heaviest carbon (12C13C {$<$} 20) may have come from s-process poor + J- and R-type carbon stars. Four small groups of grains, which + appear to require a minimum of four distinct SiC sources, have been + identified in a compilation of 308 individual SiC analyses but the + overall lack of groupings in the compilation suggest that either + there were a large number of stellar sources or that there were a + few sources whose isotopic compositions varied considerably. Simple + calculations suggest that one could expect 10 to 100 AGB stars to + have contributed SiC to a protosolar system embedded in a mature + molecular cloud. Even a few 10s of sources are enough to explain + the apparent differences seen in the various studies of Murchison + SiC and, with the exception of Inman, the differences observed from + meteorite to meteorite. This number of sources would also appear to + favor galactic chemical evolution as the explanation of the slope + 1.3 array formed by SiC in silicon three isotope plots rather than + explanations which appeal to a single star or rare high mass AGB + stars.}, + langid = {english}, } @article{SiC-1993-HOP-0, - title = {Fingerprints of Carbon, Nitrogen, and Silicon Isotopes in Small Interstellar {{SiC}} Grains from the {{Murchison}} Meteorite}, - author = {Hoppe, Peter and Geiss, Johannes and B{\"u}hler, Fritz and Neuenschwander, J{\"u}rg and Amari, Sachiko and Lewis, Roy S.}, - year = {1993}, + title = {Fingerprints of Carbon, Nitrogen, and Silicon Isotopes in Small + Interstellar {{SiC}} Grains from the {{Murchison}} Meteorite}, + author = {Hoppe, Peter and Geiss, Johannes and B{\"u}hler, Fritz and + Neuenschwander, J{\"u}rg and Amari, Sachiko and Lewis, Roy S.}, + year = 1993, month = aug, journal = {Geochimica et Cosmochimica Acta}, volume = {57}, @@ -531,14 +1022,41 @@ @article{SiC-1993-HOP-0 issn = {0016-7037}, doi = {10.1016/0016-7037(93)90353-X}, urldate = {2023-01-26}, - abstract = {We report ion microprobe determinations of the carbon, nitrogen, and silicon isotopic compositions of small SiC grains (0.2--2.4 {$\mu$}m) from the Murchison CM2 chondrite. Analyses were made on samples containing variable numbers of grains (of sizes 0.2--1 {$\mu$}m) and on fourteen individual grains (1.3--2.4 {$\mu$}m). In some cases the multiple-grain sample compositions were probably dominated by only one or two grains. Total ranges observed are: 2.9 {$<$} 12C13C {$<$} 106, 92 {$<$} 14N15N {$<$} 2700, -152 {$<$} {$\delta$}29Si {$<$} 141‰, and -216 {$<$} {$\delta$}30Si {$<$} 104‰. Only a few grains show values near the range limits. Both the total ranges of carbon and nitrogen isotopic compositions, and even the narrower ranges typical for the majority of the grains (12C13C {\textasciitilde} 40--100, 14N15N {\textasciitilde} 400--2000), are similar to those observed for larger ({$>$}2 {$\mu$}m) SiC grains. Two rare components appear .to be present in the smaller-size fraction (0.2--1 {$\mu$}m), one characterized by 12C13C {\textasciitilde} 12-16 and the other (not directly observed) by very heavy nitrogen (14N15N {$<$} 100). The carbon and nitrogen isotopic compositions qualitatively may reflect hydrostatic H-burning via the CNO cycle and He-burning in red giants (most grains), as well as explosive H-burning in novae. The silicon isotopic compositions of most grains qualitatively show what is the signature of He-burning (enrichment in 29Si and 30Si). The silicon isotopic composition of one grain, however, suggests a different process.}, - langid = {english} + abstract = {We report ion microprobe determinations of the carbon, nitrogen, + and silicon isotopic compositions of small SiC grains (0.2--2.4 {$ + \mu$}m) from the Murchison CM2 chondrite. Analyses were made on + samples containing variable numbers of grains (of sizes 0.2--1 {$ + \mu$}m) and on fourteen individual grains (1.3--2.4 {$\mu$}m). In + some cases the multiple-grain sample compositions were probably + dominated by only one or two grains. Total ranges observed are: 2.9 + {$<$} 12C13C {$<$} 106, 92 {$<$} 14N15N {$<$} 2700, -152 {$<$} {$ + \delta$}29Si {$<$} 141‰, and -216 {$<$} {$\delta$}30Si {$<$} 104‰. + Only a few grains show values near the range limits. Both the total + ranges of carbon and nitrogen isotopic compositions, and even the + narrower ranges typical for the majority of the grains (12C13C + \textasciitilde{} 40--100, 14N15N \textasciitilde{} 400--2000), are + similar to those observed for larger ({$>$}2 {$\mu$}m) SiC grains. + Two rare components appear .to be present in the smaller-size + fraction (0.2--1 {$\mu$}m), one characterized by 12C13C + \textasciitilde{} 12-16 and the other (not directly observed) by + very heavy nitrogen (14N15N {$<$} 100). The carbon and nitrogen + isotopic compositions qualitatively may reflect hydrostatic + H-burning via the CNO cycle and He-burning in red giants (most + grains), as well as explosive H-burning in novae. The silicon + isotopic compositions of most grains qualitatively show what is the + signature of He-burning (enrichment in 29Si and 30Si). The silicon + isotopic composition of one grain, however, suggests a different + process.}, + langid = {english}, } @article{SiC-1994-HOP-0, - title = {Carbon, {{Nitrogen}}, {{Magnesium}}, {{Silicon}}, and {{Titanium}} Isotopic Compositions of Single Interstellar Silicon Carbide Grains from the {{Murchison}} Carbonaceous Chondrite}, - author = {Hoppe, Peter and Amari, Sachiko and Zinner, Ernst and Ireland, Trevor and Lewis, Roy S.}, - year = {1994}, + title = {Carbon, {{Nitrogen}}, {{Magnesium}}, {{Silicon}}, and {{Titanium}} + Isotopic Compositions of Single Interstellar Silicon Carbide Grains + from the {{Murchison}} Carbonaceous Chondrite}, + author = {Hoppe, Peter and Amari, Sachiko and Zinner, Ernst and Ireland, + Trevor and Lewis, Roy S.}, + year = 1994, month = aug, journal = {The Astrophysical Journal}, volume = {430}, @@ -546,15 +1064,61 @@ @article{SiC-1994-HOP-0 issn = {0004-637X}, doi = {10.1086/174458}, urldate = {2023-01-26}, - abstract = {Seven hundred and twenty SiC grains from the Murchison CM2 chondrite, ranging in size from 1 to 10 micrometers, were analyzed by ion microprobe mass spectrometry for their C-isotopic compositions. Subsets of the grains were also analyzed for N (450 grains), Si (183 grains), Mg (179 grains), and Ti (28 grains) isotopes. These results are compared with previous measurements on 41 larger SiC grains (up to 15 x 26 micrometers) from a different sample of Murchison analyzed by Virag et al. (1992) and Ireland, Zinner, \& Amari (1991a). All grains of the present study are isotopically anomalous with C-12/C-13 ratios ranging from 0.022 to 28.4 x solar, N-14/N-15 ratios from 0.046 to 30 x solar, Si-29/Si-28 from 0.54 to 1.20 x solar, Si-30/Si-28 from 0.42 to 1.14 x solar, Ti-49/Ti-48 from 0.96 to 1.95 x solar, and Ti-50/Ti-48 from 0.94 to 1.39 x solar. Many grains have large Mg-26 excesses from the decay of Al-26 with inferred Al-26/Al-27 ratios ranging up to 0.61, or 12,200 x the ratio of 5 x 10-5 inferred for the early solar system. Several groups can be distinguished among the SiC grains. Most of the grains have C-13 and N-14 excesses, and their Si isotopic compositions (mostly excesses in Si-29 and Si-30) plot close to a slope 1.34 line on a Delta Si-29/Si-28 versus Delta Si-30/Si-28 three-isotope plot. Grains with small C-12/C-13 ratios (less than 10) tend to have smaller or no N-14 excesses and high Al-26/Al-27 ratios (up to 0.01). Grains with C-12/C-13 greater than 150 fall into two groups: grains X have N-15 excesses and Si-29 and Si-30 deficits and the highest (0.1 to 0.6) Al-26/Al-27 ratios; grains Y have N-14 excesses and plot on a slope 0.35 line on a Si three-isotope plot. In addition, large SiC grains of the Virag et al. (1992) study fall into three-distinct clusters according to their C-, Si-, and Ti-isotopic compositions. The isotopic diversity of the grains and the clustering of their isotopic compositions imply distinct and multiple stellar sources. The C- and N-isotopic compositions of most grains are consistent with H-burning in the CNO cycle. These and s-process Kr, Xe, Ba, and Nd suggest asymptotic giant branch (AGB) or Wolf-Rayet stars as likely sources for the grains, but existing models of nucleosynthesis in these stellar sites fail to account in detail for all the observed isotopic compositions. Special problems are posed by grains with C-12/C-13 less than 10 and almost normal and heavy N-isotopic compositions. Also the Si- and Ti-isotopic compositions, with excesses in Si-29 and Si-30 relative to Si-28 and excesses in all Ti isotopes relative to Ti-48, do not precisely conform with the compositions predicted for slow neutron capture. Additional theoretical efforts are needed to achieve an understanding of the isotopic composition of the SiC grains and their stellar sources.}, - annotation = {ADS Bibcode: 1994ApJ...430..870H} + abstract = {Seven hundred and twenty SiC grains from the Murchison CM2 + chondrite, ranging in size from 1 to 10 micrometers, were analyzed + by ion microprobe mass spectrometry for their C-isotopic + compositions. Subsets of the grains were also analyzed for N (450 + grains), Si (183 grains), Mg (179 grains), and Ti (28 grains) + isotopes. These results are compared with previous measurements on + 41 larger SiC grains (up to 15 x 26 micrometers) from a different + sample of Murchison analyzed by Virag et al. (1992) and Ireland, + Zinner, \& Amari (1991a). All grains of the present study are + isotopically anomalous with C-12/C-13 ratios ranging from 0.022 to + 28.4 x solar, N-14/N-15 ratios from 0.046 to 30 x solar, + Si-29/Si-28 from 0.54 to 1.20 x solar, Si-30/Si-28 from 0.42 to + 1.14 x solar, Ti-49/Ti-48 from 0.96 to 1.95 x solar, and + Ti-50/Ti-48 from 0.94 to 1.39 x solar. Many grains have large Mg-26 + excesses from the decay of Al-26 with inferred Al-26/Al-27 ratios + ranging up to 0.61, or 12,200 x the ratio of 5 x 10-5 inferred for + the early solar system. Several groups can be distinguished among + the SiC grains. Most of the grains have C-13 and N-14 excesses, and + their Si isotopic compositions (mostly excesses in Si-29 and Si-30) + plot close to a slope 1.34 line on a Delta Si-29/Si-28 versus Delta + Si-30/Si-28 three-isotope plot. Grains with small C-12/C-13 ratios + (less than 10) tend to have smaller or no N-14 excesses and high + Al-26/Al-27 ratios (up to 0.01). Grains with C-12/C-13 greater than + 150 fall into two groups: grains X have N-15 excesses and Si-29 and + Si-30 deficits and the highest (0.1 to 0.6) Al-26/Al-27 ratios; + grains Y have N-14 excesses and plot on a slope 0.35 line on a Si + three-isotope plot. In addition, large SiC grains of the Virag et + al. (1992) study fall into three-distinct clusters according to + their C-, Si-, and Ti-isotopic compositions. The isotopic diversity + of the grains and the clustering of their isotopic compositions + imply distinct and multiple stellar sources. The C- and N-isotopic + compositions of most grains are consistent with H-burning in the + CNO cycle. These and s-process Kr, Xe, Ba, and Nd suggest + asymptotic giant branch (AGB) or Wolf-Rayet stars as likely sources + for the grains, but existing models of nucleosynthesis in these + stellar sites fail to account in detail for all the observed + isotopic compositions. Special problems are posed by grains with + C-12/C-13 less than 10 and almost normal and heavy N-isotopic + compositions. Also the Si- and Ti-isotopic compositions, with + excesses in Si-29 and Si-30 relative to Si-28 and excesses in all + Ti isotopes relative to Ti-48, do not precisely conform with the + compositions predicted for slow neutron capture. Additional + theoretical efforts are needed to achieve an understanding of the + isotopic composition of the SiC grains and their stellar sources.}, } @article{SiC-1996-HOP-0, - title = {Small {{SiC}} Grains and a Nitride Grain of Circumstellar Origin from the {{Murchison}} Meteorite: {{Implications}} for Stellar Evolution and Nucleosynthesis}, - shorttitle = {Small {{SiC}} Grains and a Nitride Grain of Circumstellar Origin from the {{Murchison}} Meteorite}, - author = {Hoppe, Peter and Strebel, Roger and Eberhardt, Peter and Amari, Sachiko and Lewis, Roy S.}, - year = {1996}, + title = {Small {{SiC}} Grains and a Nitride Grain of Circumstellar Origin from + the {{Murchison}} Meteorite: {{Implications}} for Stellar Evolution + and Nucleosynthesis}, + shorttitle = {Small {{SiC}} Grains and a Nitride Grain of Circumstellar Origin + from the {{Murchison}} Meteorite}, + author = {Hoppe, Peter and Strebel, Roger and Eberhardt, Peter and Amari, + Sachiko and Lewis, Roy S.}, + year = 1996, month = mar, journal = {Geochimica et Cosmochimica Acta}, volume = {60}, @@ -563,14 +1127,49 @@ @article{SiC-1996-HOP-0 issn = {0016-7037}, doi = {10.1016/0016-7037(95)00435-1}, urldate = {2023-01-26}, - abstract = {We report the results of SIMS isotopic analyses of carbon, nitrogen, oxygen, and silicon made on 849 small ({$\approx$} 1 {$\mu$}m) individual silicon carbide grains from the Murchison meteorite. The isotopic compositions of the major elements carbon and silicon of most grains (mainstream) are similar to those observed in larger grain studies suggesting an AGB star origin of these grains. In contrast, the trace element nitrogen shows a clear dependency on grain size. 14N/15N ratios increase with decreasing grain size, suggesting different stellar sources for grains of different size. Typically observed 14N/15N ratios in the small grains of this study are {$\approx$}2700, clearly larger than the values expected from model calculations of AGB stars. In addition to the three dredge-up episodes characteristic for the evolution of AGB stars, extra-mixing of CNO-processed matter in low-mass AGB stars appears to be a promising possibility in order to explain the high 14N/15N ratios of the small circumstellar SiC grains. A small fraction of grains shows a silicon isotopic signature not observed in larger circumstellar SiC grains from Murchison. Their stellar origin is still uncertain. The minor type A, B, Y, and X grains were found to be present at a level of a percent, which is similar to their abundance in the larger-grain SiC separates from Murchison. Oxygen isotopic compositions are normal within the experimental uncertainties of several 10\%, indicating that oxygen of stellar origin is rare or even absent in the SiC grains. We conclude that most of the oxygen is a contaminant which was introduced into the SiC grains after their formation, e.g., during sample processing in the laboratoy. We identified a nitride grain, most likely Si3N4 with little carbon, with highly anomalous isotopic compositions (12C/13C = 157 {\textpm} 33, 14N/15N = 18 {\textpm} 1, {$\delta$}29Si = -43 {\textpm} 56‰, {$\delta$}30Si = -271 {\textpm} 50‰). The isotopic patterns of carbon, nitrogen, and silicon resemble those of the rare SiC X grains suggesting that these two rare constituents of circumstellar matter formed in the same type of stellar source, namely, Type II supernovae.}, - langid = {english} + abstract = {We report the results of SIMS isotopic analyses of carbon, + nitrogen, oxygen, and silicon made on 849 small ({$\approx$} 1 {$ + \mu$}m) individual silicon carbide grains from the Murchison + meteorite. The isotopic compositions of the major elements carbon + and silicon of most grains (mainstream) are similar to those + observed in larger grain studies suggesting an AGB star origin of + these grains. In contrast, the trace element nitrogen shows a clear + dependency on grain size. 14N/15N ratios increase with decreasing + grain size, suggesting different stellar sources for grains of + different size. Typically observed 14N/15N ratios in the small + grains of this study are {$\approx$}2700, clearly larger than the + values expected from model calculations of AGB stars. In addition + to the three dredge-up episodes characteristic for the evolution of + AGB stars, extra-mixing of CNO-processed matter in low-mass AGB + stars appears to be a promising possibility in order to explain the + high 14N/15N ratios of the small circumstellar SiC grains. A small + fraction of grains shows a silicon isotopic signature not observed + in larger circumstellar SiC grains from Murchison. Their stellar + origin is still uncertain. The minor type A, B, Y, and X grains + were found to be present at a level of a percent, which is similar + to their abundance in the larger-grain SiC separates from + Murchison. Oxygen isotopic compositions are normal within the + experimental uncertainties of several 10\%, indicating that oxygen + of stellar origin is rare or even absent in the SiC grains. We + conclude that most of the oxygen is a contaminant which was + introduced into the SiC grains after their formation, e.g., during + sample processing in the laboratoy. We identified a nitride grain, + most likely Si3N4 with little carbon, with highly anomalous + isotopic compositions (12C/13C = 157 \textpm{} 33, 14N/15N = 18 + \textpm{} 1, {$\delta$}29Si = -43 \textpm{} 56‰, {$\delta$}30Si = + -271 \textpm{} 50‰). The isotopic patterns of carbon, nitrogen, and + silicon resemble those of the rare SiC X grains suggesting that + these two rare constituents of circumstellar matter formed in the + same type of stellar source, namely, Type II supernovae.}, + langid = {english}, } @article{SiC-1996-HOP-1, - title = {Type {{II}} Supernova Matter in a Silicon Carbide Grain from the {{Murchison}} Meteorite}, - author = {Hoppe, Peter and Strebel, Roger and Eberhardt, Peter and Amari, Sachiko and Lewis, Roy S.}, - year = {1996}, + title = {Type {{II}} Supernova Matter in a Silicon Carbide Grain from the {{ + Murchison}} Meteorite}, + author = {Hoppe, Peter and Strebel, Roger and Eberhardt, Peter and Amari, + Sachiko and Lewis, Roy S.}, + year = 1996, month = may, journal = {Science}, volume = {272}, @@ -579,28 +1178,57 @@ @article{SiC-1996-HOP-1 publisher = {American Association for the Advancement of Science}, doi = {10.1126/science.272.5266.1314}, urldate = {2023-01-26}, - abstract = {The circumstellar silicon carbide (SiC) grain X57 from the Murchison meteorite contains large amounts of radiogenic calcium-44 (20 times its solar system abundance) and has an anomalous silicon isotopic composition, different from other circumstellar SiC grains. Its inferred initial 44Ti/Si and 44Ti/48Ti ratios are 1.6 {\texttimes} 10-4 and 0.37. In addition, it contains radiogenic magnesium-26; the inferred initial 26Al/27Al ratio is 0.11. The isotopic and elemental data of X57 can be explained by selective mixing of matter from different zones of a typical type II supernova of 25 solar masses during its explosion. The high 44Ti/Si ratio requires contributions from the innermost nickel zone of the supernova to the SiC condensation site, as similarly suggested by astronomical observations.} + abstract = {The circumstellar silicon carbide (SiC) grain X57 from the + Murchison meteorite contains large amounts of radiogenic calcium-44 + (20 times its solar system abundance) and has an anomalous silicon + isotopic composition, different from other circumstellar SiC + grains. Its inferred initial 44Ti/Si and 44Ti/48Ti ratios are 1.6 + \texttimes{} 10-4 and 0.37. In addition, it contains radiogenic + magnesium-26; the inferred initial 26Al/27Al ratio is 0.11. The + isotopic and elemental data of X57 can be explained by selective + mixing of matter from different zones of a typical type II + supernova of 25 solar masses during its explosion. The high 44Ti/Si + ratio requires contributions from the innermost nickel zone of the + supernova to the SiC condensation site, as similarly suggested by + astronomical observations.}, } @inproceedings{SiC-1996-HOP-2, - title = {Origin of Circumstellar {{SiC}} Grains with Low {\textsuperscript{12}}{{C}}/{\textsuperscript{13}}{{C}} Ratios: {{A}} Multiple Star Scenario}, - shorttitle = {Origin of {{Circumstellar SiC Grains With Low 12C}}/{{13C Ratios}}}, + title = {Origin of Circumstellar {{SiC}} Grains with Low {$^{12}$} {{C}}/{$^{ + 13}$}{{C}} Ratios: {{A}} Multiple Star Scenario}, + shorttitle = {Origin of {{Circumstellar SiC Grains With Low 12C}}/{{13C Ratios + }}}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Hoppe, P. and Kocher, T. A. and Strebel, R. and Eberhardt, P. and Amari, S. and Lewis, R. S.}, - year = {1996}, + author = {Hoppe, P. and Kocher, T. A. and Strebel, R. and Eberhardt, P. and + Amari, S. and Lewis, R. S.}, + year = 1996, month = mar, volume = {27}, pages = {561}, urldate = {2023-01-26}, - abstract = {In a search for the rare SiC grains of types A and B (12C/13C {$<$}= 10 we have screened approximately 2000 SiC grains from Murchison separate KJE (average size 1.14 micrometers by ion imaging and subsequently analyzed candidate grains together with approximately 200 SiC grains from Murchison separate KJC (average size 0.67 micrometers) by conventional analysis technique with the University of Bern ion microprobe. Together with our data previously obtained for separate KJE we now have C-, N-, MgAl-, and Si-isotopic data of 73 A and B grains (not all elements on all grains. The C- and N-isotopic data can be reproduced remarkably well by a simple model mixing CNO- and He-burning products. The previously postulated origin of the A and B grains in J-type carbon stars and CH stars is supported by our new data. For one grain with 14N/15N = 7, however, a nova origin is a realistic possibility.}, - annotation = {ADS Bibcode: 1996LPI....27..561H} + abstract = {In a search for the rare SiC grains of types A and B (12C/13C {$<$ + } = 10 we have screened approximately 2000 SiC grains from + Murchison separate KJE (average size 1.14 micrometers by ion + imaging and subsequently analyzed candidate grains together with + approximately 200 SiC grains from Murchison separate KJC (average + size 0.67 micrometers) by conventional analysis technique with the + University of Bern ion microprobe. Together with our data + previously obtained for separate KJE we now have C-, N-, MgAl-, and + Si-isotopic data of 73 A and B grains (not all elements on all + grains. The C- and N-isotopic data can be reproduced remarkably + well by a simple model mixing CNO- and He-burning products. The + previously postulated origin of the A and B grains in J-type carbon + stars and CH stars is supported by our new data. For one grain with + 14N/15N = 7, however, a nova origin is a realistic possibility.}, } @article{SiC-1996-NIT-0, - title = {Extinct {\textsuperscript{44}}{{Ti}} in Presolar Graphite and {{SiC}}: {{Proof}} of a Supernova Origin}, + title = {Extinct {$^{44}$}{{Ti}} in Presolar Graphite and {{SiC}} : {{Proof}} + of a Supernova Origin}, shorttitle = {Extinct {{44Ti}} in {{Presolar Graphite}} and {{SiC}}}, - author = {Nittler, Larry R. and Amari, Sachiko and Zinner, Ernst and Woosley, S. E. and Lewis, Roy S.}, - year = {1996}, + author = {Nittler, Larry R. and Amari, Sachiko and Zinner, Ernst and Woosley, + S. E. and Lewis, Roy S.}, + year = 1996, month = may, journal = {The Astrophysical Journal}, volume = {462}, @@ -609,36 +1237,57 @@ @article{SiC-1996-NIT-0 issn = {0004-637X}, doi = {10.1088/1538-4357/462/1/L31}, urldate = {2023-01-26}, - abstract = {Large excesses in 44Ca, from the radioactive decay of short-lived 44Ti, have been observed in four low-density graphite grains and five SiC grains of type X extracted from the Murchison meteorite. Titanium-46,49Ti, and 50Ti excesses were also observed in several of these grains. Because 44Ti is only produced in supernovae, these grains must have a supernova origin. Moreover, Si-, C-, N-, Al-, O-, and Ti-isotopic compositions of the grains require a Type II supernova source, and indicate extensive and heterogeneous mixing of different supernova regions, including the nickel core.}, - langid = {english} + abstract = {Large excesses in 44Ca, from the radioactive decay of short-lived + 44Ti, have been observed in four low-density graphite grains and + five SiC grains of type X extracted from the Murchison meteorite. + Titanium-46,49Ti, and 50Ti excesses were also observed in several + of these grains. Because 44Ti is only produced in supernovae, these + grains must have a supernova origin. Moreover, Si-, C-, N-, Al-, O- + , and Ti-isotopic compositions of the grains require a Type II + supernova source, and indicate extensive and heterogeneous mixing + of different supernova regions, including the nickel core.}, + langid = {english}, } @phdthesis{SiC-1996-NIT-1, - title = {Quantitative Isotopic Ratio Ion Imaging and Its Application to Studies of Preserved Stardust in Meteorites}, + title = {Quantitative Isotopic Ratio Ion Imaging and Its Application to + Studies of Preserved Stardust in Meteorites}, author = {Nittler, Larry R}, - year = {1996}, + year = 1996, address = {St. Louis, Missouri}, - school = {Washington University} + school = {Washington University}, } @inproceedings{SiC-1997-GAO-0, - title = {{\textsuperscript{30}}{{Si-enriched}} Presolar {{SiC}} in {{Acfer}} 094}, + title = {{$^{30}$}{{Si-enriched}} Presolar {{SiC}} in {{Acfer}} 094}, booktitle = {Lunar and {{Planetary Science Conference}}}, author = {Gao, X. and Nittler, L. R.}, - year = {1997}, + year = 1997, month = mar, volume = {28}, pages = {1769}, urldate = {2023-01-26}, - abstract = {Ion imaging of Si-28/Si-30 ratios of SiC in the Acfer 094 meteorite identified a group of SiC grains with larger Si-30 enrichments than previously measured in presolar SiC in other meteorites. These grains, present at a level of about 0.2 percent of the 'mainstream' SiC, are less abundant than some previously discovered SiC subgroups. Grains of such low abundance are practically impossible to find using conventioanl techniques. The identification of three such grains is reported here in addition to two which were presented earlier (Gao et al., 1996), as well as one new Z-subgroup type SiC grain.}, - annotation = {ADS Bibcode: 1997LPI....28..393G} + abstract = {Ion imaging of Si-28/Si-30 ratios of SiC in the Acfer 094 + meteorite identified a group of SiC grains with larger Si-30 + enrichments than previously measured in presolar SiC in other + meteorites. These grains, present at a level of about 0.2 percent + of the 'mainstream' SiC, are less abundant than some previously + discovered SiC subgroups. Grains of such low abundance are + practically impossible to find using conventioanl techniques. The + identification of three such grains is reported here in addition to + two which were presented earlier (Gao et al., 1996), as well as one + new Z-subgroup type SiC grain.}, } @article{SiC-1997-HOP-0, - title = {Meteoritic Silicon Carbide Grains with Unusual {{Si-isotopic}} Compositions: {{Evidence}} for an Origin in Low-Mass, Low-Metallicity Asymptotic Giant Branch Stars}, - shorttitle = {Meteoritic {{Silicon Carbide Grains}} with {{Unusual S}}[{{CLC}}]i[/{{CLC}}]-{{Isotopic Compositions}}}, - author = {Hoppe, P. and Annen, P. and Strebel, R. and Eberhardt, P. and Gallino, R. and Lugaro, M. and Amari, S. and Lewis, R. S.}, - year = {1997}, + title = {Meteoritic Silicon Carbide Grains with Unusual {{Si-isotopic}} + Compositions: {{Evidence}} for an Origin in Low-Mass, Low-Metallicity + Asymptotic Giant Branch Stars}, + shorttitle = {Meteoritic {{Silicon Carbide Grains}} with {{Unusual S}}[{{CLC}} + ]i[/{{CLC}}]-{{Isotopic Compositions}}}, + author = {Hoppe, P. and Annen, P. and Strebel, R. and Eberhardt, P. and + Gallino, R. and Lugaro, M. and Amari, S. and Lewis, R. S.}, + year = 1997, month = sep, journal = {The Astrophysical Journal}, volume = {487}, @@ -646,14 +1295,17 @@ @article{SiC-1997-HOP-0 pages = {L101-L104}, issn = {0004637X}, doi = {10.1086/310869}, - urldate = {2023-01-26} + urldate = {2023-01-26}, } @article{SiC-1997-HUS-0, - title = {Isotopic Systematics of Presolar Silicon Carbide from the {{Orgueil}} ({{CI}}) Chondrite: {{Implications}} for Solar System Formation and Stellar Nucleosynthesis}, - shorttitle = {Isotopic Systematics of Presolar Silicon Carbide from the {{Orgueil}} ({{CI}}) Chondrite}, + title = {Isotopic Systematics of Presolar Silicon Carbide from the {{Orgueil}} + ({{CI}}) Chondrite: {{Implications}} for Solar System Formation and + Stellar Nucleosynthesis}, + shorttitle = {Isotopic Systematics of Presolar Silicon Carbide from the {{ + Orgueil}} ({{CI}}) Chondrite}, author = {Huss, Gary R. and Hutcheon, Ian D. and Wasserburg, G. J.}, - year = {1997}, + year = 1997, month = dec, journal = {Geochimica et Cosmochimica Acta}, volume = {61}, @@ -662,14 +1314,74 @@ @article{SiC-1997-HUS-0 issn = {0016-7037}, doi = {10.1016/S0016-7037(97)00299-8}, urldate = {2023-01-27}, - abstract = {One hundred and forty individual SiC grains (1--9.6 {$\mu$}m) and twenty-two grain aggregates (2.3--7.8 {$\mu$}m) from the Orgueil (CI) chondrite have been measured by ion microprobe. Silicon and carbon isotopic data were obtained for all individual grains and aggregates, and nitrogen, magnesium, and aluminum abundances and isotopic compositions were measured for most grains and aggregates. Abundances of lithium, beryllium, boron, and sodium were measured for some individual grains. Orgueil SiC is remarkably similar to Murchison K-series SiC in the ranges and distributions of silicon and carbon isotopic compositions, the initial abundances of 26Al, the abundances of minor and trace elements, and the proportions of isotopically unusual grains. Higher 15N14N ratios in 1--4 {$\mu$}m Murchison K-series SiC grains relative to similar-sized Orgueil grains are inferred to be due to higher amounts of terrestrial nitrogen in the Murchison samples. Higher 15N14N ratios in 3--6 {$\mu$}m Murchison KJH SiC grains cannot be explained by terrestrial nitrogen and imply that larger SiC grains sampled a different population of parent stars. SiC aggregates have different average silicon and carbon compositions than individual grains, indicating different source stars for the 0.1--1 {$\mu$}m constituent grains. However, the aggregates probably formed by clumping of small grains during laboratory procedures, not at the stellar source. Differences between Murchison L-series SiC and SiC from Murchison K-series and Orgueil are due to the presence of terrestrial SiC among L-series grains and to the larger average grain size of L-series SiC. When terrestrial contamination, sample size, and grain size are taken into account, there is no evidence of an intrinsic difference between Orgueil and Murchison SiC. The Orgueil data provide new information about stellar nucleosynthesis and the SiC parent stars. Carbon and nitrogen isotopic compositions indicate that nuclear processing in addition to that described by most stellar models occurs below the convective stellar envelope during the Red Giant and AGB phases (Cool Bottom Processing). Grains with high 15N14N but with other characteristics consistent with AGB source stars indicate that 15N is produced in AGB stars, contrary to the predictions of the standard models. A significantly higher rate for the 180({$\alpha$}, n)15N reaction than is typically used might reconcile the models with the observations. No data currently rule out a higher reaction rate. Addition of 180 produced via 14N ({$\alpha$}, {$\psi$})180 below the hydrogen shell and burned to 15N in the envelope may also play a role in producing the high 15N14N ratios observed in some SiC grains. Following previous workers, we take the slope {$\sim$}2.2 silicon isotope array defined by mainstream SiC grains to reflect the initial compositions of the parent stars due to galactic evolution. A general correlation between 12C13C and 29,30Si28Si and more scatter around the silicon array at low 29,30Si28Si indicate that SiC grains with higher 29,30Si28Si ratios come from higher-metallicity parent stars. A lack of resolved isotopic effects in 25Mg24Mg suggests that variations in initial magnesium compositions of the parent stars are at least a factor of three smaller than those in silicon and that the 22Ne neutron source was not significantly activated in the AGB stars that produced SiC grains, in accord with theory. These observations indicate that the parent stars of most mainstream SiC grains were {$\leq$}2.3 M{$\odot$} and experienced enough Third Dredge-up thermal pulses to supply their envelopes with 2--3\% helium,shell material. A few grains have characteristics suggesting that they came from more-massive stars. Most parent stars of {$>$} 1 {$\mu$}m SiC grains apparently had metallicities higher than that of the sun.}, - langid = {english} + abstract = {One hundred and forty individual SiC grains (1--9.6 {$\mu$}m) and + twenty-two grain aggregates (2.3--7.8 {$\mu$}m) from the Orgueil + (CI) chondrite have been measured by ion microprobe. Silicon and + carbon isotopic data were obtained for all individual grains and + aggregates, and nitrogen, magnesium, and aluminum abundances and + isotopic compositions were measured for most grains and aggregates. + Abundances of lithium, beryllium, boron, and sodium were measured + for some individual grains. Orgueil SiC is remarkably similar to + Murchison K-series SiC in the ranges and distributions of silicon + and carbon isotopic compositions, the initial abundances of 26Al, + the abundances of minor and trace elements, and the proportions of + isotopically unusual grains. Higher 15N14N ratios in 1--4 {$\mu$}m + Murchison K-series SiC grains relative to similar-sized Orgueil + grains are inferred to be due to higher amounts of terrestrial + nitrogen in the Murchison samples. Higher 15N14N ratios in 3--6 {$ + \mu$}m Murchison KJH SiC grains cannot be explained by terrestrial + nitrogen and imply that larger SiC grains sampled a different + population of parent stars. SiC aggregates have different average + silicon and carbon compositions than individual grains, indicating + different source stars for the 0.1--1 {$\mu$}m constituent grains. + However, the aggregates probably formed by clumping of small grains + during laboratory procedures, not at the stellar source. + Differences between Murchison L-series SiC and SiC from Murchison + K-series and Orgueil are due to the presence of terrestrial SiC + among L-series grains and to the larger average grain size of + L-series SiC. When terrestrial contamination, sample size, and + grain size are taken into account, there is no evidence of an + intrinsic difference between Orgueil and Murchison SiC. The Orgueil + data provide new information about stellar nucleosynthesis and the + SiC parent stars. Carbon and nitrogen isotopic compositions + indicate that nuclear processing in addition to that described by + most stellar models occurs below the convective stellar envelope + during the Red Giant and AGB phases (Cool Bottom Processing). + Grains with high 15N14N but with other characteristics consistent + with AGB source stars indicate that 15N is produced in AGB stars, + contrary to the predictions of the standard models. A significantly + higher rate for the 180({$\alpha$}, n)15N reaction than is + typically used might reconcile the models with the observations. No + data currently rule out a higher reaction rate. Addition of 180 + produced via 14N ({$\alpha$}, {$\psi$})180 below the hydrogen shell + and burned to 15N in the envelope may also play a role in producing + the high 15N14N ratios observed in some SiC grains. Following + previous workers, we take the slope {$\sim$}2.2 silicon isotope + array defined by mainstream SiC grains to reflect the initial + compositions of the parent stars due to galactic evolution. A + general correlation between 12C13C and 29,30Si28Si and more scatter + around the silicon array at low 29,30Si28Si indicate that SiC + grains with higher 29,30Si28Si ratios come from higher-metallicity + parent stars. A lack of resolved isotopic effects in 25Mg24Mg + suggests that variations in initial magnesium compositions of the + parent stars are at least a factor of three smaller than those in + silicon and that the 22Ne neutron source was not significantly + activated in the AGB stars that produced SiC grains, in accord with + theory. These observations indicate that the parent stars of most + mainstream SiC grains were {$\leq$}2.3 M{$\odot$} and experienced + enough Third Dredge-up thermal pulses to supply their envelopes + with 2--3\% helium,shell material. A few grains have + characteristics suggesting that they came from more-massive stars. + Most parent stars of {$>$} 1 {$\mu$}m SiC grains apparently had + metallicities higher than that of the sun.}, + langid = {english}, } @article{SiC-1997-NIC-0, title = {S-Process Zirconium in Presolar Silicon Carbide Grains}, - author = {Nicolussi, G{\"u}nther K. and Davis, Andrew M. and Pellin, Michael J. and Lewis, Roy S. and Clayton, Robert N. and Amari, Sachiko}, - year = {1997}, + author = {Nicolussi, G{\"u}nther K. and Davis, Andrew M. and Pellin, Michael + J. and Lewis, Roy S. and Clayton, Robert N. and Amari, Sachiko}, + year = 1997, month = aug, journal = {Science}, volume = {277}, @@ -678,13 +1390,25 @@ @article{SiC-1997-NIC-0 publisher = {American Association for the Advancement of Science}, doi = {10.1126/science.277.5330.1281}, urldate = {2023-01-27}, - abstract = {The isotopic composition of zirconium in silicon carbide grains from the Murchison meteorite was measured by resonant ionization mass spectrometry of laser-ablated neutral atoms. These grains are condensates from the atmospheres of red giant stars that existed before the formation of our sun and solar system, and they contain records of nucleosynthesis in these stars. The r-process--dominated isotope zirconium-96 was depleted by more than a factor of 2 compared with the s-process--dominated isotopes zirconium-90, zirconium-91, zirconium-92, and zirconium-94, in agreement with expectations for neutron capture nucleosynthesis in asymptotic giant branch stars.} + abstract = {The isotopic composition of zirconium in silicon carbide grains + from the Murchison meteorite was measured by resonant ionization + mass spectrometry of laser-ablated neutral atoms. These grains are + condensates from the atmospheres of red giant stars that existed + before the formation of our sun and solar system, and they contain + records of nucleosynthesis in these stars. The r-process--dominated + isotope zirconium-96 was depleted by more than a factor of 2 + compared with the s-process--dominated isotopes zirconium-90, + zirconium-91, zirconium-92, and zirconium-94, in agreement with + expectations for neutron capture nucleosynthesis in asymptotic + giant branch stars.}, } @article{SiC-1998-NIC-0, - title = {Molybdenum Isotopic Composition of Individual Presolar Silicon Carbide Grains from the {{Murchison}} Meteorite}, - author = {Nicolussi, G. K. and Pellin, M. J. and Lewis, R. S. and Davis, A. M. and Amari, S. and Clayton, R. N.}, - year = {1998}, + title = {Molybdenum Isotopic Composition of Individual Presolar Silicon + Carbide Grains from the {{Murchison}} Meteorite}, + author = {Nicolussi, G. K. and Pellin, M. J. and Lewis, R. S. and Davis, A. M. + and Amari, S. and Clayton, R. N.}, + year = 1998, month = mar, journal = {Geochimica et Cosmochimica Acta}, volume = {62}, @@ -693,15 +1417,34 @@ @article{SiC-1998-NIC-0 issn = {0016-7037}, doi = {10.1016/S0016-7037(98)00038-6}, urldate = {2023-01-27}, - abstract = {We report the isotopic composition of molybdenum in twenty-three presolar SiC grains from the Murchison meteorite which have been measured by resonant ionization mass spectrometry (RIMS). Relative to terrestrial abundance (and normalized to s-process-only 96Mo), the majority of the analyzed grains show strong depletions in the p-process isotopes 92Mo and 94Mo and the r-process isotope 100Mo. Sixteen of these grains have {$\delta$}-values {$<-$}600\% for these three isotopes. The observed isotopic patterns of Mo from mainstream SiC grains clearly reveal the signature of s-process nucleosynthesis. Three-isotope plots of all grain data ({$\delta$}iMo vs. {$\delta$}92Mo) show strong linear correlations with characteristic slopes. This finding suggests mixing of solar-like material and pure s-process material in the parent stars. Comparison with evolutionary calculations of nucleosynthesis and mixing in red giants suggests that low-mass thermally-pulsed symptotic giant branch (TP-AGB) stars are the most likely site for the observed s-process nucleosynthesis.}, - langid = {english} + abstract = {We report the isotopic composition of molybdenum in twenty-three + presolar SiC grains from the Murchison meteorite which have been + measured by resonant ionization mass spectrometry (RIMS). Relative + to terrestrial abundance (and normalized to s-process-only 96Mo), + the majority of the analyzed grains show strong depletions in the + p-process isotopes 92Mo and 94Mo and the r-process isotope 100Mo. + Sixteen of these grains have {$\delta$}-values {$<$}-600\% for + these three isotopes. The observed isotopic patterns of Mo from + mainstream SiC grains clearly reveal the signature of s-process + nucleosynthesis. Three-isotope plots of all grain data ({$\delta$} + iMo vs. {$\delta$}92Mo) show strong linear correlations with + characteristic slopes. This finding suggests mixing of solar-like + material and pure s-process material in the parent stars. + Comparison with evolutionary calculations of nucleosynthesis and + mixing in red giants suggests that low-mass thermally-pulsed + symptotic giant branch (TP-AGB) stars are the most likely site for + the observed s-process nucleosynthesis.}, + langid = {english}, } @article{SiC-1998-NIC-1, - title = {Strontium Isotopic Composition in Individual Circumstellar Silicon Carbide Grains: {{A}} Record of {\emph{s}}-Process Nucleosynthesis}, - shorttitle = {Strontium {{Isotopic Composition}} in {{Individual Circumstellar Silicon Carbide Grains}}}, - author = {Nicolussi, G. K. and Pellin, M. J. and Lewis, R. S. and Davis, A. M. and Clayton, R. N. and Amari, S.}, - year = {1998}, + title = {Strontium Isotopic Composition in Individual Circumstellar Silicon + Carbide Grains: {{A}} Record of {\emph{s}}-Process Nucleosynthesis}, + shorttitle = {Strontium {{Isotopic Composition}} in {{Individual Circumstellar + Silicon Carbide Grains}}}, + author = {Nicolussi, G. K. and Pellin, M. J. and Lewis, R. S. and Davis, A. M. + and Clayton, R. N. and Amari, S.}, + year = 1998, month = oct, journal = {Physical Review Letters}, volume = {81}, @@ -710,13 +1453,21 @@ @article{SiC-1998-NIC-1 publisher = {American Physical Society}, doi = {10.1103/PhysRevLett.81.3583}, urldate = {2023-01-27}, - abstract = {Twenty six individual circumstellar SiC grains extracted from the Murchison meteorite were analyzed for their strontium isotopic compositions by resonant ionization mass spectrometry. Large abundance deficits were found for the p-process isotope 84Sr. The measured grains had 87Sr/86Sr ratios indistinguishable from the primordial solar value, but several grains differed in their 88Sr/86Sr ratios as a consequence of the branch point at 85Kr. The Sr isotopic data are consistent with s-process nucleosynthesis at moderate neutron densities.} + abstract = {Twenty six individual circumstellar SiC grains extracted from the + Murchison meteorite were analyzed for their strontium isotopic + compositions by resonant ionization mass spectrometry. Large + abundance deficits were found for the p-process isotope 84Sr. The + measured grains had 87Sr/86Sr ratios indistinguishable from the + primordial solar value, but several grains differed in their + 88Sr/86Sr ratios as a consequence of the branch point at 85Kr. The + Sr isotopic data are consistent with s-process nucleosynthesis at + moderate neutron densities.}, } @article{SiC-1999-ALE-0, title = {The Galactic Evolution of {{Si}}, {{Ti}}, and {{O}} Isotopic Ratios}, author = {Alexander, C. M. O'D. and Nittler, Larry R.}, - year = {1999}, + year = 1999, month = jul, journal = {The Astrophysical Journal}, volume = {519}, @@ -726,13 +1477,14 @@ @article{SiC-1999-ALE-0 issn = {0004-637X}, doi = {10.1086/307340}, urldate = {2023-01-27}, - langid = {english} + langid = {english}, } @article{SiC-1999-AMA-0, - title = {A Singular Presolar {{SiC}} Grain with Extreme {\textsuperscript{29}}{{Si}} and {\textsuperscript{30}}{{Si}} Excesses}, + title = {A Singular Presolar {{SiC}} Grain with Extreme {$^{29}$} {{Si}} and { + $^{30}$}{{Si}} Excesses}, author = {Amari, Sachiko and Zinner, Ernst and Lewis, Roy S.}, - year = {1999}, + year = 1999, month = apr, journal = {The Astrophysical Journal}, volume = {517}, @@ -741,14 +1493,25 @@ @article{SiC-1999-AMA-0 issn = {0004-637X}, doi = {10.1086/312013}, urldate = {2023-01-27}, - abstract = {An ion-imaging search of presolar SiC grains from the Murchison meteorite revealed one grain whose isotopic ratios are highly unusual: 12C/13C = 844{\textpm}34, 14N/15N = 213{\textpm}21, 29Si/28Si = (3.68{\textpm}0.02) times solar, and 30Si/28Si = (4.29{\textpm}0.04) times solar. Although several populations of presolar SiC grains have been identified, most of which originate in low-mass asymptotic giant branch stars, this is the first grain of its kind among 20,000 SiC grains analyzed to date. Type II supernovae and Wolf-Rayet O binary systems are possible stellar sources.}, - langid = {english} + abstract = {An ion-imaging search of presolar SiC grains from the Murchison + meteorite revealed one grain whose isotopic ratios are highly + unusual: 12C/13C = 844\textpm 34, 14N/15N = 213\textpm 21, + 29Si/28Si = (3.68\textpm 0.02) times solar, and 30Si/28Si = (4.29 + \textpm 0.04) times solar. Although several populations of presolar + SiC grains have been identified, most of which originate in + low-mass asymptotic giant branch stars, this is the first grain of + its kind among 20,000 SiC grains analyzed to date. Type II + supernovae and Wolf-Rayet O binary systems are possible stellar + sources.}, + langid = {english}, } @article{SiC-2000-HOP-0, - title = {Isotopic Properties of Silicon Carbide {{X}} Grains from the {{Murchison}} Meteorite in the Size Range 0.5-1.5 {$M$}m}, - author = {Hoppe, Peter and Strebel, Roger and Eberhardt, Peter and Amari, Sachiko and Lewis, Roy S.}, - year = {2000}, + title = {Isotopic Properties of Silicon Carbide {{X}} Grains from the {{ + Murchison}} Meteorite in the Size Range 0.5-1.5 {{Mm}}}, + author = {Hoppe, Peter and Strebel, Roger and Eberhardt, Peter and Amari, + Sachiko and Lewis, Roy S.}, + year = 2000, journal = {Meteoritics \& Planetary Science}, volume = {35}, number = {6}, @@ -756,27 +1519,86 @@ @article{SiC-2000-HOP-0 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2000.tb01505.x}, urldate = {2023-01-27}, - abstract = {Abstract--- We report isotopic abundances for C, N, Mg-Al, Si, Ca-Ti, and Fe in 99 presolar silicon carbide (SiC) grains of type X (84 grains from this work and 15 grains from previous studies) from the Murchison CM2 meteorite, ranging in size from 0.5 to 1.5 {$\mu$}m. Carbon was measured in 41 X grains, n in 37 grains, Mg-Al in 18 grains, Si in 87 grains, Ca-Ti in 25 grains, and Fe in 8 grains. These X grains have 12C/13C ratios between 18 and 6800, 14N/15n ratios from 13 to 200, {$\delta$}29Si/28Si between -750 and +60\%0, {$\delta$}30Si/28Si from -770 to -10\%0, and 54Fe/56Fe ratios that are compatible with solar within the analytical uncertainties of several tens of percent. Many X grains carry large amounts of radiogenic 26Mg (from the radioactive decay of 26Al, half-life {$\cong$} 7 times 105 years) and radiogenic 44Ca (from the radioactive decay of 44Ti, half-life = 60 years). While all X grains but one have radiogenic 26Mg, only {$\sim$}20\% of them have detectable amounts of radiogenic 44Ca. Initial 26Al/27Al ratios of up to 0.36 and initial 44Ti/48Ti ratios of up to 0.56 can be inferred. The isotopic data are compared with those expected from the potential stellar sources of SiC dust. Carbon stars, Wolf-Rayet stars, and novae are ruled out as stellar sources of the X grains. The isotopic compositions of C and Fe and abundances of extinct 44Ti are well explained both by type Ia and type II supernova (SN) models. The same holds for 26Al/27Al ratios, except for the highest 26Al/27Al ratios of {$>$}0.2 in some X grains. Silicon agrees qualitatively with SN model predictions, but the observed 29Si/30Si ratios in the X grains are in most cases too high, pointing to deficiencies in the current understanding of the production of Si in SN environments. The measured 14n/15n ratios are lower than those expected from SN mixing models. This problem can be overcome in a 15 Modot; type II SN if rotational mixing, preferential trapping of N, or both from 15n-rich regions in the ejecta are considered. The isotopic characteristics of C, N, Si, and initial 26Al/27Al ratios in small X grains are remarkably similar to those of large X grains (2--10 {$\mu$}m). Titanium-44 concentrations are generally much higher in smaller grains, indicative of the presence of Ti-bearing subgrains that might have served as condensation nuclei for SiC. The fraction of X grains among presolar SiC is largely independent of grain size. This implies similar grain-size distributions for SiC from carbon stars (mainstream grains) and supernovae (X grains), a surprising conclusion in view of the different conditions for dust formation in these two types of stellar sources.}, - langid = {english} + abstract = {Abstract--- We report isotopic abundances for C, N, Mg-Al, Si, + Ca-Ti, and Fe in 99 presolar silicon carbide (SiC) grains of type X + (84 grains from this work and 15 grains from previous studies) from + the Murchison CM2 meteorite, ranging in size from 0.5 to 1.5 {$\mu$ + } m. Carbon was measured in 41 X grains, n in 37 grains, Mg-Al in + 18 grains, Si in 87 grains, Ca-Ti in 25 grains, and Fe in 8 grains. + These X grains have 12C/13C ratios between 18 and 6800, 14N/15n + ratios from 13 to 200, {$\delta$}29Si/28Si between -750 and +60\%0, + {$\delta$}30Si/28Si from -770 to -10\%0, and 54Fe/56Fe ratios that + are compatible with solar within the analytical uncertainties of + several tens of percent. Many X grains carry large amounts of + radiogenic 26Mg (from the radioactive decay of 26Al, half-life {$ + \cong$} 7 times 105 years) and radiogenic 44Ca (from the + radioactive decay of 44Ti, half-life = 60 years). While all X + grains but one have radiogenic 26Mg, only {$\sim$}20\% of them have + detectable amounts of radiogenic 44Ca. Initial 26Al/27Al ratios of + up to 0.36 and initial 44Ti/48Ti ratios of up to 0.56 can be + inferred. The isotopic data are compared with those expected from + the potential stellar sources of SiC dust. Carbon stars, Wolf-Rayet + stars, and novae are ruled out as stellar sources of the X grains. + The isotopic compositions of C and Fe and abundances of extinct + 44Ti are well explained both by type Ia and type II supernova (SN) + models. The same holds for 26Al/27Al ratios, except for the highest + 26Al/27Al ratios of {$>$}0.2 in some X grains. Silicon agrees + qualitatively with SN model predictions, but the observed 29Si/30Si + ratios in the X grains are in most cases too high, pointing to + deficiencies in the current understanding of the production of Si + in SN environments. The measured 14n/15n ratios are lower than + those expected from SN mixing models. This problem can be overcome + in a 15 Modot; type II SN if rotational mixing, preferential + trapping of N, or both from 15n-rich regions in the ejecta are + considered. The isotopic characteristics of C, N, Si, and initial + 26Al/27Al ratios in small X grains are remarkably similar to those + of large X grains (2--10 {$\mu$}m). Titanium-44 concentrations are + generally much higher in smaller grains, indicative of the presence + of Ti-bearing subgrains that might have served as condensation + nuclei for SiC. The fraction of X grains among presolar SiC is + largely independent of grain size. This implies similar grain-size + distributions for SiC from carbon stars (mainstream grains) and + supernovae (X grains), a surprising conclusion in view of the + different conditions for dust formation in these two types of + stellar sources.}, + langid = {english}, } @techreport{SiC-2000-PEL-0, - title = {Zr and {{Mo}} Isotopic Constraints on the Origins of Unusual Types of Presolar {{SiC}} Grains.}, - author = {Pellin, M. J. and Davis, A. M. and Calaway, W. F. and Lewis, R. S. and Clayton, R. N. and Amari, S.}, - year = {2000}, + title = {Zr and {{Mo}} Isotopic Constraints on the Origins of Unusual Types of + Presolar {{SiC}} Grains.}, + author = {Pellin, M. J. and Davis, A. M. and Calaway, W. F. and Lewis, R. S. + and Clayton, R. N. and Amari, S.}, + year = 2000, month = mar, number = {ANL/CHM/CP-101227}, institution = {Argonne National Lab., IL (US)}, urldate = {2023-01-27}, - abstract = {Although most presolar silicon carbide grains form in asymptotic giant branch red giant stars (the so-called mainstream grains) or supernovae (the X-grains), there are a number of other minor types of grains whose origin is less clear. The dominant mechanisms of heavy element nucleosynthesis, the s-process and r-process, are thought to occur mainly in AGB stars and supernovae, respectively [1], and the isotopic patterns in heavy elements in presolar grains can be used to constrain their origins. We have previously reported that mainstream SiC grains have strong enrichments in the s-process isotopes of Sr, Zr and Mo [2-5] and that X-grains have an unusual Mo isotopic composition that differs from s- and r-process expectations [6,7]. We report here the first measurements of Zr and Mo isotopes in several grains of other rare types that were found in the same mount as the mainstream and X-grains reported previously.}, - langid = {english} + abstract = {Although most presolar silicon carbide grains form in asymptotic + giant branch red giant stars (the so-called mainstream grains) or + supernovae (the X-grains), there are a number of other minor types + of grains whose origin is less clear. The dominant mechanisms of + heavy element nucleosynthesis, the s-process and r-process, are + thought to occur mainly in AGB stars and supernovae, respectively + [1], and the isotopic patterns in heavy elements in presolar grains + can be used to constrain their origins. We have previously reported + that mainstream SiC grains have strong enrichments in the s-process + isotopes of Sr, Zr and Mo [2-5] and that X-grains have an unusual + Mo isotopic composition that differs from s- and r-process + expectations [6,7]. We report here the first measurements of Zr and + Mo isotopes in several grains of other rare types that were found + in the same mount as the mainstream and X-grains reported + previously.}, + langid = {english}, } @article{SiC-2001-AMA-0, - title = {Presolar {{SiC}} Grains of Type {{Y}}: {{Origin}} from Low-Metallicity Asymptotic Giant Branch Stars}, + title = {Presolar {{SiC}} Grains of Type {{Y}}: {{Origin}} from + Low-Metallicity Asymptotic Giant Branch Stars}, shorttitle = {Presolar {{SiC Grains}} of {{Type Y}}}, - author = {Amari, Sachiko and Nittler, Larry R. and Zinner, Ernst and Gallino, Roberto and Lugaro, Maria and Lewis, Roy S.}, - year = {2001}, + author = {Amari, Sachiko and Nittler, Larry R. and Zinner, Ernst and Gallino, + Roberto and Lugaro, Maria and Lewis, Roy S.}, + year = 2001, month = jan, journal = {The Astrophysical Journal}, volume = {546}, @@ -785,14 +1607,58 @@ @article{SiC-2001-AMA-0 issn = {0004-637X}, doi = {10.1086/318230}, urldate = {2023-01-27}, - abstract = {We report isotopic data for 27 presolar SiC grains of the rare subtype Y in an acid-resistant residue of the Murchison (CM2) meteorite. Presolar SiC grains of type Y constitute only 1\% of Murchison SiC grains larger than 2 {$\mu$}m and are defined as having 12C/13C {$>$} 100 (solar = 89) and 14N/15N {$>$} 272 (solar). In a Si 3-isotope plot, their Si isotopic compositions plot to the right of the correlation line defined by the majority of presolar SiC grains (the mainstream population), whose isotopic compositions indicate an origin in C-rich asymptotic giant branch (AGB) stars of near-solar metallicity. Because of their low abundance, the new Y grains were identified by automatic isotopic imaging of the 12C/13C ratio in the ion microprobe. We report C, N, and Si isotopic ratios of all 27 grains, inferred initial 26Al/27Al ratios of 18, and Ti isotopic ratios of 20 grains. Whereas 14N/15N and 26Al/27Al ratios exhibit the same range as mainstream grains, the C, Si, and Ti isotopic ratios are distinct. Carbon-12/carbon-13 ratios range up to 295 and 30Si/28Si excesses up to 183‰ relative to solar. The average 29Si/28Si ratio of Y grains is by 59‰ smaller than that of mainstream grains. Ti isotopic ratios relative to 48Ti are somewhat similar to those of mainstream grains, but extend to more extreme anomalous compositions. One grain has 46Ti/48Ti, 49Ti/48Ti, and 50Ti/48Ti excesses of 183‰, 365‰, and 990‰, respectively, relative to solar. These features exhibited by Y grains point to an origin in AGB stars of somewhat lower than solar metallicity. In the envelope of such stars the proportion of 12C and s-processed material dredged up from deep zones that experienced partial He burning and was mixed with original material is higher than in stars of solar metallicity. Their envelopes are therefore expected to have larger 12C/13C, 30Si/28Si, and 49Ti/48Ti and 50Ti/48Ti ratios than mainstream grains. We compare the C, Si, and Ti isotopic compositions of Y grains with the results of theoretical models of AGB stars with 1.5, 3, and 5 M{$\Sun$} and Z = 0.006, 0.01, and 0.02. While solar-metallicity (Z = 0.02) AGB models cannot account for the Y grain data, the models with Z = 0.01 can reproduce the measured isotopic compositions reasonably well. A range of stellar masses (from 1.5 M{$\Sun$} possibly up to 5 M{$\Sun$}) is indicated by the grain data. The present study together with additional data on SiC grains of type Z furthermore indicate that the rate of change of the ratios of the secondary Si isotopes (29Si and 30Si) relative to 28Si prior to solar system formation was lower than has been generally assumed, implying larger contributions of 28Si from Type Ia supernovae compared to those from Type II supernovae. The Si isotopic ratios of Galactic cosmic rays also suggest such an evolution.}, - langid = {english} + abstract = {We report isotopic data for 27 presolar SiC grains of the rare + subtype Y in an acid-resistant residue of the Murchison (CM2) + meteorite. Presolar SiC grains of type Y constitute only 1\% of + Murchison SiC grains larger than 2 {$\mu$}m and are defined as + having 12C/13C {$>$} 100 (solar = 89) and 14N/15N {$>$} 272 + (solar). In a Si 3-isotope plot, their Si isotopic compositions + plot to the right of the correlation line defined by the majority + of presolar SiC grains (the mainstream population), whose isotopic + compositions indicate an origin in C-rich asymptotic giant branch + (AGB) stars of near-solar metallicity. Because of their low + abundance, the new Y grains were identified by automatic isotopic + imaging of the 12C/13C ratio in the ion microprobe. We report C, N, + and Si isotopic ratios of all 27 grains, inferred initial 26Al/27Al + ratios of 18, and Ti isotopic ratios of 20 grains. Whereas 14N/15N + and 26Al/27Al ratios exhibit the same range as mainstream grains, + the C, Si, and Ti isotopic ratios are distinct. Carbon-12/carbon-13 + ratios range up to 295 and 30Si/28Si excesses up to 183‰ relative + to solar. The average 29Si/28Si ratio of Y grains is by 59‰ smaller + than that of mainstream grains. Ti isotopic ratios relative to 48Ti + are somewhat similar to those of mainstream grains, but extend to + more extreme anomalous compositions. One grain has 46Ti/48Ti, + 49Ti/48Ti, and 50Ti/48Ti excesses of 183‰, 365‰, and 990‰, + respectively, relative to solar. These features exhibited by Y + grains point to an origin in AGB stars of somewhat lower than solar + metallicity. In the envelope of such stars the proportion of 12C + and s-processed material dredged up from deep zones that + experienced partial He burning and was mixed with original material + is higher than in stars of solar metallicity. Their envelopes are + therefore expected to have larger 12C/13C, 30Si/28Si, and 49Ti/48Ti + and 50Ti/48Ti ratios than mainstream grains. We compare the C, Si, + and Ti isotopic compositions of Y grains with the results of + theoretical models of AGB stars with 1.5, 3, and 5 M{$\Sun$} and Z + = 0.006, 0.01, and 0.02. While solar-metallicity (Z = 0.02) AGB + models cannot account for the Y grain data, the models with Z = + 0.01 can reproduce the measured isotopic compositions reasonably + well. A range of stellar masses (from 1.5 M{$\Sun$} possibly up to + 5 M{$\Sun$}) is indicated by the grain data. The present study + together with additional data on SiC grains of type Z furthermore + indicate that the rate of change of the ratios of the secondary Si + isotopes (29Si and 30Si) relative to 28Si prior to solar system + formation was lower than has been generally assumed, implying + larger contributions of 28Si from Type Ia supernovae compared to + those from Type II supernovae. The Si isotopic ratios of Galactic + cosmic rays also suggest such an evolution.}, + langid = {english}, } @article{SiC-2001-AMA-1, title = {Presolar Grains from Novae}, - author = {Amari, Sachiko and Gao, Xia and Nittler, Larry R. and Zinner, Ernst and Jos{\'e}, Jordi and Hernanz, Margarita and Lewis, Roy S.}, - year = {2001}, + author = {Amari, Sachiko and Gao, Xia and Nittler, Larry R. and Zinner, Ernst + and Jos{\'e}, Jordi and Hernanz, Margarita and Lewis, Roy S.}, + year = 2001, month = apr, journal = {The Astrophysical Journal}, volume = {551}, @@ -801,15 +1667,36 @@ @article{SiC-2001-AMA-1 issn = {0004-637X}, doi = {10.1086/320235}, urldate = {2023-01-27}, - abstract = {We report the discovery of five SiC grains and one graphite grain isolated from the Murchison carbonaceous meteorite whose major-element isotopic compositions indicate an origin in nova explosions. The grains are characterized by low 12C/13C (4-9) and 14N/15N (5-20) ratios, large excesses in 30Si (30Si/28Si ratios range to 2.1 times solar), and high 26Al/27Al ratios. These isotopic signatures are theoretically predicted for the ejecta from ONe novae and cannot be matched by any other stellar sources. Previous studies of presolar grains from primitive meteorites have shown that the vast majority formed in red giant outflows and supernova ejecta. Although a classical nova origin was suggested for a few presolar graphite grains on the basis of 22Ne enrichments, this identification is somewhat ambiguous since it is based on only one trace element. Our present study presents the first evidence for nova grains on the basis of major element isotopic compositions of single grains. We also present the results of nucleosynthetic calculations of classical nova models and compare the predicted isotopic ratios with those of the grains. The comparison points toward massive ONe novae if the ejecta are mixed with material of close-to-solar composition.}, - langid = {english} + abstract = {We report the discovery of five SiC grains and one graphite grain + isolated from the Murchison carbonaceous meteorite whose + major-element isotopic compositions indicate an origin in nova + explosions. The grains are characterized by low 12C/13C (4-9) and + 14N/15N (5-20) ratios, large excesses in 30Si (30Si/28Si ratios + range to 2.1 times solar), and high 26Al/27Al ratios. These + isotopic signatures are theoretically predicted for the ejecta from + ONe novae and cannot be matched by any other stellar sources. + Previous studies of presolar grains from primitive meteorites have + shown that the vast majority formed in red giant outflows and + supernova ejecta. Although a classical nova origin was suggested + for a few presolar graphite grains on the basis of 22Ne enrichments + , this identification is somewhat ambiguous since it is based on + only one trace element. Our present study presents the first + evidence for nova grains on the basis of major element isotopic + compositions of single grains. We also present the results of + nucleosynthetic calculations of classical nova models and compare + the predicted isotopic ratios with those of the grains. The + comparison points toward massive ONe novae if the ejecta are mixed + with material of close-to-solar composition.}, + langid = {english}, } @article{SiC-2001-AMA-2, - title = {Presolar {{SiC}} Grains of Type {{A}} and {{B}}: {{Their}} Isotopic Compositions and Stellar Origins}, + title = {Presolar {{SiC}} Grains of Type {{A}} and {{B}}: {{Their}} Isotopic + Compositions and Stellar Origins}, shorttitle = {Presolar {{SiC Grains}} of {{Type A}} and {{B}}}, - author = {Amari, Sachiko and Nittler, Larry R. and Zinner, Ernst and Lodders, Katharina and Lewis, Roy S.}, - year = {2001}, + author = {Amari, Sachiko and Nittler, Larry R. and Zinner, Ernst and Lodders, + Katharina and Lewis, Roy S.}, + year = 2001, month = sep, journal = {The Astrophysical Journal}, volume = {559}, @@ -818,21 +1705,65 @@ @article{SiC-2001-AMA-2 issn = {0004-637X}, doi = {10.1086/322397}, urldate = {2023-01-27}, - abstract = {A total of 124 presolar SiC grains of type A and B (defined as having 12C/13C {$<$} 10) were identified by ion imaging in an acid-resistant residue of the Murchison carbonaceous meteorite. Their isotopic ratios, together with those of 28 previously analyzed A+B grains, are reported here. The 14N/15N ratios range from 39 to 104, with one-third of the grains having 14N/15N ratios lower than the solar value of 272. Inferred 26Al/27Al ratios of A+B grains range up to 10-2. These isotopic compositions clearly distinguish A+B grains from other presolar SiC populations. Among the A+B grains, grains with lower 12C/13C ratios tend to have lower 14N/15N and higher 26Al/27Al ratios. Silicon of A+B grains is enriched in the neutron-rich isotopes (29Si/28Si up to 1.20 times solar, 30Si/28Si up to 1.13 times solar), and in an Si three-isotope plot the distribution of the isotopic ratios is very similar to that of mainstream grains, indicating that the parent stars of the A+B grains had close-to-solar metallicity. Titanium isotopic ratios of 13 grains, out of 30 analyzed, deviate from solar by more than 2 {$\sigma$} in at least one isotopic ratio and span the same range as those of mainstream grains. Trace element abundance patterns of 20 previously measured A+B grains indicate that seven condensed from an atmosphere without s-process enrichments, while 13 did so from an atmosphere enriched in s-process elements by 3-5 times solar. Observationally, the most likely sources of A+B grains with solar s-process abundances are J-type carbon stars, but the origin of these stars is unclear. Born-again asymptotic giant branch (AGB) stars, typified by Sakurai's object (V4334 Sgr), are possible sources of A+B grains with enhanced s-process elemental abundances. Other C-rich stars with low 12C/13C ratios including R stars and CH stars are less likely stellar sources. Whatever the stellar sources, both H and He burning as well as mixing must have occurred in the proper combination to produce both low 12C/13C ratios and C {$>$} O in the envelope. A special nucleosynthetic problem is posed by the 14N/15N ratios of the grains. High ratios can be explained by hot bottom burning and by cool bottom processing in thermally pulsing AGB stars. Another proposed scenario that possibly yields this signature is extensive mixing of He-burning material into the H-rich envelope during the core He flash. However, the spread of the 14N/15N ratios and lower-than-solar 14N/15N ratios remains unexplained. The isotopic and elemental compositions of A+B grains can provide new information about nucleosynthesis in their possible parent stars that cannot be obtained in any other way.}, - langid = {english} + abstract = {A total of 124 presolar SiC grains of type A and B (defined as + having 12C/13C {$<$} 10) were identified by ion imaging in an + acid-resistant residue of the Murchison carbonaceous meteorite. + Their isotopic ratios, together with those of 28 previously + analyzed A+B grains, are reported here. The 14N/15N ratios range + from 39 to 104, with one-third of the grains having 14N/15N ratios + lower than the solar value of 272. Inferred 26Al/27Al ratios of A+B + grains range up to 10-2. These isotopic compositions clearly + distinguish A+B grains from other presolar SiC populations. Among + the A+B grains, grains with lower 12C/13C ratios tend to have lower + 14N/15N and higher 26Al/27Al ratios. Silicon of A+B grains is + enriched in the neutron-rich isotopes (29Si/28Si up to 1.20 times + solar, 30Si/28Si up to 1.13 times solar), and in an Si + three-isotope plot the distribution of the isotopic ratios is very + similar to that of mainstream grains, indicating that the parent + stars of the A+B grains had close-to-solar metallicity. Titanium + isotopic ratios of 13 grains, out of 30 analyzed, deviate from + solar by more than 2 {$\sigma$} in at least one isotopic ratio and + span the same range as those of mainstream grains. Trace element + abundance patterns of 20 previously measured A+B grains indicate + that seven condensed from an atmosphere without s-process + enrichments, while 13 did so from an atmosphere enriched in + s-process elements by 3-5 times solar. Observationally, the most + likely sources of A+B grains with solar s-process abundances are + J-type carbon stars, but the origin of these stars is unclear. + Born-again asymptotic giant branch (AGB) stars, typified by + Sakurai's object (V4334 Sgr), are possible sources of A+B grains + with enhanced s-process elemental abundances. Other C-rich stars + with low 12C/13C ratios including R stars and CH stars are less + likely stellar sources. Whatever the stellar sources, both H and He + burning as well as mixing must have occurred in the proper + combination to produce both low 12C/13C ratios and C {$>$} O in the + envelope. A special nucleosynthetic problem is posed by the 14N/15N + ratios of the grains. High ratios can be explained by hot bottom + burning and by cool bottom processing in thermally pulsing AGB + stars. Another proposed scenario that possibly yields this + signature is extensive mixing of He-burning material into the + H-rich envelope during the core He flash. However, the spread of + the 14N/15N ratios and lower-than-solar 14N/15N ratios remains + unexplained. The isotopic and elemental compositions of A+B grains + can provide new information about nucleosynthesis in their possible + parent stars that cannot be obtained in any other way.}, + langid = {english}, } @phdthesis{SiC-2001-BES-0, - title = {Si-, {{Mg-}}, {{Ca-}} Und {{Ti-Isotopenmessungen}} an Den Pr{\"a}solaren {{Mineralen Diamant}}, {{Siliziumkarbid}} Und {{Siliziumnitrid}} Aus Kohligen Und {{Enstatit-Chondriten}}}, + title = {Si-, {{Mg-}}, {{Ca-}} Und {{Ti-Isotopenmessungen}} an Den Pr\"a + Solaren {{Mineralen Diamant}}, {{Siliziumkarbid}} Und {{Siliziumnitrid + }} Aus Kohligen Und {{Enstatit-Chondriten}}}, author = {Besmehn, Astrid}, - year = {2001}, - school = {Universit{\"a}t Mainz} + year = 2001, + school = {Universit\"at Mainz}, } @article{SiC-2001-HOP-0, title = {Boron in Presolar Silicon Carbide Grains from Supernovae}, - author = {Hoppe, P. and Lodders, K. and Strebel, R. and Amari, S. and Lewis, R. S.}, - year = {2001}, + author = {Hoppe, P. and Lodders, K. and Strebel, R. and Amari, S. and Lewis, + R. S.}, + year = 2001, month = apr, journal = {The Astrophysical Journal}, volume = {551}, @@ -841,27 +1772,53 @@ @article{SiC-2001-HOP-0 issn = {0004-637X}, doi = {10.1086/320075}, urldate = {2023-01-27}, - abstract = {Eleven presolar silicon carbide grains of type X separated from the Murchison meteorite have been analyzed for boron abundances and isotopic compositions by secondary ion mass spectrometry. Boron concentrations are low with typical B/Si ratios of {$\approx$} 1 {\texttimes} 10-5. The average 11B/10B ratio of 3.46 {\textpm} 1.39 is compatible with the solar system value but might be affected by contaminating boron of laboratory origin. These data are compared with theoretical predictions for Type II supernovae, the most likely parent stars of X grains. The B/Si ratios of X grains are much lower (more than an order of magnitude on average) than expected from Type II supernova shell-mixing of matter from the C- and Si-rich zones, contrary to other elemental ratios such as Al/Si and Ti/Si. Condensation calculations show that with C/O {$>$} 1 in the ejecta, boron and aluminum will readily condense as BN and AlN, respectively, into silicon carbide, and the B/Al ratio is expected to remain constant. The nitrogen, aluminum, and titanium abundances in SiC X grains are well reproduced by the condensation calculations. Given the similarity of the boron and aluminum condensation chemistry and the generally expected high B/Al ratios (relative to solar) in Type II supernova mixtures with C/O {$>$} 1, the observed difference between measured and predicted B/Al ratios must be considered a serious problem. Possible solutions include (1) lower than predicted boron production from Type II supernovae, (2) complex mixing scenarios in supernova ejecta involving only sublayers of the C-rich zones, and (3) formation of silicon carbide under conditions with C/O {$<$} 0.1.}, - langid = {english} + abstract = {Eleven presolar silicon carbide grains of type X separated from + the Murchison meteorite have been analyzed for boron abundances and + isotopic compositions by secondary ion mass spectrometry. Boron + concentrations are low with typical B/Si ratios of {$\approx$} 1 + \texttimes{} 10-5. The average 11B/10B ratio of 3.46 \textpm{} 1.39 + is compatible with the solar system value but might be affected by + contaminating boron of laboratory origin. These data are compared + with theoretical predictions for Type II supernovae, the most + likely parent stars of X grains. The B/Si ratios of X grains are + much lower (more than an order of magnitude on average) than + expected from Type II supernova shell-mixing of matter from the C- + and Si-rich zones, contrary to other elemental ratios such as Al/Si + and Ti/Si. Condensation calculations show that with C/O {$>$} 1 in + the ejecta, boron and aluminum will readily condense as BN and AlN, + respectively, into silicon carbide, and the B/Al ratio is expected + to remain constant. The nitrogen, aluminum, and titanium abundances + in SiC X grains are well reproduced by the condensation + calculations. Given the similarity of the boron and aluminum + condensation chemistry and the generally expected high B/Al ratios + (relative to solar) in Type II supernova mixtures with C/O {$>$} 1, + the observed difference between measured and predicted B/Al ratios + must be considered a serious problem. Possible solutions include + (1) lower than predicted boron production from Type II supernovae, + (2) complex mixing scenarios in supernova ejecta involving only + sublayers of the C-rich zones, and (3) formation of silicon carbide + under conditions with C/O {$<$} 0.1.}, + langid = {english}, } @inproceedings{SiC-2002-JEN-0, title = {Indarch {{SiC}} by {{TIMS}}, {{RIMS}}, and {{NanoSIMS}}}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Jennings, C. L. and Savina, M. R. and Messenger, S. and Amari, S. and Nichols, Jr., R. H. and Pellin, M. J. and Podosek, F. A.}, - year = {2002}, + author = {Jennings, C. L. and Savina, M. R. and Messenger, S. and Amari, S. + and Nichols, Jr., R. H. and Pellin, M. J. and Podosek, F. A.}, + year = 2002, month = mar, volume = {33}, pages = {1833}, urldate = {2023-01-27}, - abstract = {We have measured the Ba isotopic composition in Indarch SiC (separates and individual grains) by TIMS, RIMS and nanoSIMS.}, - annotation = {ADS Bibcode: 2002LPI....33.1833J} + abstract = {We have measured the Ba isotopic composition in Indarch SiC + (separates and individual grains) by TIMS, RIMS and nanoSIMS.}, } @article{SiC-2002-LIN-0, title = {Presolar Grains from the {{Qingzhen}} ({{EH3}}) Meteorite}, author = {Lin, Yangting and Amari, Sachiko and Pravdivtseva, Olga}, - year = {2002}, + year = 2002, month = aug, journal = {The Astrophysical Journal}, volume = {575}, @@ -870,26 +1827,45 @@ @article{SiC-2002-LIN-0 issn = {0004-637X}, doi = {10.1086/341218}, urldate = {2023-01-27}, - abstract = {A 28 g sample of the Qingzhen enstatite (EH3) chondrite was subjected to chemical and physical separation procedures to yield several grain-size residues. Ion mapping of isotopes of Si, O, and C in the ion microprobe of two size fractions (QZR4: 0.4-0.8 {$\mu$}m; QZR5: 0.8-2 {$\mu$}m) identified 55 30Si-depleted candidates out of 37,917 Si-rich grains and six 18O-depleted grains out of 54,410 oxides. Subsequent isotopic analyses of C, N, and Si of 48 grains of the 30Si-depleted candidates and additional randomly selected SiC and Si3N4 grains confirmed 36 of X-type SiC, nine of X-type Si3N4, and one of A+B-type SiC. The isotopic compositions of most X grains overlap those of previously measured X grains from the Murchison carbonaceous chondrite, but 25\% show more pronounced 29Si deficits, suggestive of multiple stellar origins of X grains. Presolar Si3N4 grains have isotopic compositions similar to those of X SiC grains, except that their C isotopic ratios are close to solar. The relative abundances of various presolar grain types in Qingzhen are different from those in Murchison, suggestive of heterogeneity and/or size sorting in the primitive solar nebula.}, - langid = {english} + abstract = {A 28 g sample of the Qingzhen enstatite (EH3) chondrite was + subjected to chemical and physical separation procedures to yield + several grain-size residues. Ion mapping of isotopes of Si, O, and + C in the ion microprobe of two size fractions (QZR4: 0.4-0.8 {$\mu$ + } m; QZR5: 0.8-2 {$\mu$}m) identified 55 30Si-depleted candidates + out of 37,917 Si-rich grains and six 18O-depleted grains out of 54, + 410 oxides. Subsequent isotopic analyses of C, N, and Si of 48 + grains of the 30Si-depleted candidates and additional randomly + selected SiC and Si3N4 grains confirmed 36 of X-type SiC, nine of + X-type Si3N4, and one of A+B-type SiC. The isotopic compositions of + most X grains overlap those of previously measured X grains from + the Murchison carbonaceous chondrite, but 25\% show more pronounced + 29Si deficits, suggestive of multiple stellar origins of X grains. + Presolar Si3N4 grains have isotopic compositions similar to those + of X SiC grains, except that their C isotopic ratios are close to + solar. The relative abundances of various presolar grain types in + Qingzhen are different from those in Murchison, suggestive of + heterogeneity and/or size sorting in the primitive solar nebula.}, + langid = {english}, } @article{SiC-2003-AMA-0, - title = {Silicon and Titanium Isotopic Analysis of Silicon Carbide Grains of Type {{X}} and {{Z}}}, + title = {Silicon and Titanium Isotopic Analysis of Silicon Carbide Grains of + Type {{X}} and {{Z}}}, author = {Amari, S. and Zinner, E. and Gallino, R. and Lewis, R. S.}, - year = {2003}, + year = 2003, month = jul, journal = {Meteoritics and Planetary Science Supplement}, volume = {38}, pages = {5118}, urldate = {2023-01-27}, - langid = {english} + langid = {english}, } @article{SiC-2003-BES-0, - title = {A {{NanoSIMS}} Study of {{Si-}} and {{Ca-Ti-isotopic}} Compositions of Presolar Silicon Carbide Grains from Supernovae}, + title = {A {{NanoSIMS}} Study of {{Si-}} and {{Ca-Ti-isotopic}} Compositions + of Presolar Silicon Carbide Grains from Supernovae}, author = {Besmehn, Astrid and Hoppe, Peter}, - year = {2003}, + year = 2003, month = dec, journal = {Geochimica et Cosmochimica Acta}, series = {A {{Special Issue Dedicated}} to {{Robert M Walker}}}, @@ -899,15 +1875,43 @@ @article{SiC-2003-BES-0 issn = {0016-7037}, doi = {10.1016/S0016-7037(03)00239-4}, urldate = {2023-01-27}, - abstract = {We report results from NanoSIMS isotopic measurements on 37 presolar silicon carbide grains of type X which are believed to have formed in the ejecta of supernova explosions. Isotopic data were obtained for Si and Ca-Ti (all grains), C and N (two grains), and Ti (one grain). All X grains exhibit large enrichments in 28Si (up to 5{\texttimes} solar), in agreement with previously studied X grains. On a scale of 200 nm, the Si-isotopic ratios do not vary by more than the analytical uncertainties of several percent in all but one X grain. This implies that most X grains formed from well-mixed regions in supernova ejecta. X grain M9-68-3 is characterized by two regions with distinct Si- and Ti-isotopic signatures which may either represent two distinct grains or overgrowth of matter from two different mixtures in the supernova ejecta. Most of the Ca in the X grains is most likely contamination as indicated by close to normal 42Ca/40Ca ratios. Seven X grains show enhanced 44Ca/40Ca ratios of up to 6{\texttimes} the solar ratio. Spatial distributions of 44Ca excesses and Ti are positively correlated, giving strong support to the view that excesses in 44Ca are due to the decay of radioactive 44Ti. Inferred initial 44Ti/48Ti ratios are between 0.01 and 0.28 and are correlated with Si-isotopic ratios. Radiogenic 44Ca is widely distributed in six X grains. X grain M9-132-4 exhibits a pronounced heterogeneity in the distribution of radiogenic 44Ca and 48Ti as well as in 44Ti/48Ti, pointing to presence of a small Ti-rich subgrain or heterogeneous loss of Ca and Ti after grain formation. This grain has a unique Si-isotopic composition with 30Si/29Si = 2.2{\texttimes} the solar ratio and C- and N-isotopic compositions as typically observed in X grains.}, - langid = {english} + abstract = {We report results from NanoSIMS isotopic measurements on 37 + presolar silicon carbide grains of type X which are believed to + have formed in the ejecta of supernova explosions. Isotopic data + were obtained for Si and Ca-Ti (all grains), C and N (two grains), + and Ti (one grain). All X grains exhibit large enrichments in 28Si + (up to 5\texttimes{} solar), in agreement with previously studied X + grains. On a scale of 200 nm, the Si-isotopic ratios do not vary by + more than the analytical uncertainties of several percent in all + but one X grain. This implies that most X grains formed from + well-mixed regions in supernova ejecta. X grain M9-68-3 is + characterized by two regions with distinct Si- and Ti-isotopic + signatures which may either represent two distinct grains or + overgrowth of matter from two different mixtures in the supernova + ejecta. Most of the Ca in the X grains is most likely contamination + as indicated by close to normal 42Ca/40Ca ratios. Seven X grains + show enhanced 44Ca/40Ca ratios of up to 6\texttimes{} the solar + ratio. Spatial distributions of 44Ca excesses and Ti are positively + correlated, giving strong support to the view that excesses in 44Ca + are due to the decay of radioactive 44Ti. Inferred initial + 44Ti/48Ti ratios are between 0.01 and 0.28 and are correlated with + Si-isotopic ratios. Radiogenic 44Ca is widely distributed in six X + grains. X grain M9-132-4 exhibits a pronounced heterogeneity in the + distribution of radiogenic 44Ca and 48Ti as well as in 44Ti/48Ti, + pointing to presence of a small Ti-rich subgrain or heterogeneous + loss of Ca and Ti after grain formation. This grain has a unique + Si-isotopic composition with 30Si/29Si = 2.2\texttimes{} the solar + ratio and C- and N-isotopic compositions as typically observed in X + grains.}, + langid = {english}, } @article{SiC-2003-NIT-0, - title = {Automated Isotopic Measurements of Micron-Sized Dust: Application to Meteoritic Presolar Silicon Carbide}, + title = {Automated Isotopic Measurements of Micron-Sized Dust: {{Application}} + to Meteoritic Presolar Silicon Carbide}, shorttitle = {Automated Isotopic Measurements of Micron-Sized Dust}, author = {Nittler, Larry R. and Alexander, C. M. O'D.}, - year = {2003}, + year = 2003, month = dec, journal = {Geochimica et Cosmochimica Acta}, series = {A {{Special Issue Dedicated}} to {{Robert M Walker}}}, @@ -917,14 +1921,58 @@ @article{SiC-2003-NIT-0 issn = {0016-7037}, doi = {10.1016/S0016-7037(03)00485-X}, urldate = {2023-01-27}, - abstract = {We report the development of a new analytical system allowing the fully automated measurement of isotopic ratios in micrometer-sized particles by secondary ion mass spectrometry (SIMS) in a Cameca ims-6f ion microprobe. Scanning ion images and image processing algorithms are used to locate individual particles dispersed on sample substrates. The primary ion beam is electrostatically deflected to and focused onto each particle in turn, followed by a peak-jumping isotopic measurement. Automatic measurements of terrestrial standards indicate similar analytical uncertainties to traditional manual particle analyses (e.g., {$\sim$}3‰/amu for Si isotopic ratios). We also present an initial application of the measurement system to obtain Si and C isotopic ratios for {$\sim$}3300 presolar SiC grains from the Murchison CM2 carbonaceous chondrite. Three rare presolar Si3N4 grains were also identified and analyzed. Most of the analyzed grains were extracted from the host meteorite using a new chemical dissolution procedure. The isotopic data are broadly consistent with previous observations of presolar SiC in the same size range ({$\sim$}0.5--4 {$\mu$}m). Members of the previously identified SiC AB, X, Y, and Z subgroups were identified, as was a highly unusual grain with an extreme 30Si enrichment, a modest 29Si enrichment, and isotopically light C. The stellar source responsible for this grain is likely to have been a supernova. Minor differences in isotopic distributions between the present work and prior data can be partially explained by terrestrial contamination and grain aggregation on sample mounts, though some of the differences are probably intrinsic to the samples. We use the large new SiC database to explore the relationships between three previously identified isotopic subgroups---mainstream, Y, and Z grains---all believed to originate in asymptotic giant branch stars. The isotopic data for Z grains suggest that their parent stars experienced strong CNO-cycle nucleosynthesis during the early asymptotic giant branch phase, consistent with either cool bottom processing in low-mass (M {$<$} 2.3M{$\odot$}) parent stars or hot-bottom burning in intermediate-mass stars (M {$>$} 4M{$\odot$}). The data provide evidence for a sharp threshold in metallicity, above which SiC grains form with much higher 12C/13C ratios than below. Above this threshold, the fraction of grains with relatively high 12C/13C decreases exponentially with increasing 29Si/28Si ratio. This result indicates a sharp increase in the maximum mass of SiC parent stars with decreasing metallicity, in contrast to expectations from Galactic chemical evolution theory.}, - langid = {english} + abstract = {We report the development of a new analytical system allowing the + fully automated measurement of isotopic ratios in micrometer-sized + particles by secondary ion mass spectrometry (SIMS) in a Cameca + ims-6f ion microprobe. Scanning ion images and image processing + algorithms are used to locate individual particles dispersed on + sample substrates. The primary ion beam is electrostatically + deflected to and focused onto each particle in turn, followed by a + peak-jumping isotopic measurement. Automatic measurements of + terrestrial standards indicate similar analytical uncertainties to + traditional manual particle analyses (e.g., {$\sim$}3‰/amu for Si + isotopic ratios). We also present an initial application of the + measurement system to obtain Si and C isotopic ratios for {$\sim$} + 3300 presolar SiC grains from the Murchison CM2 carbonaceous + chondrite. Three rare presolar Si3N4 grains were also identified + and analyzed. Most of the analyzed grains were extracted from the + host meteorite using a new chemical dissolution procedure. The + isotopic data are broadly consistent with previous observations of + presolar SiC in the same size range ({$\sim$}0.5--4 {$\mu$}m). + Members of the previously identified SiC AB, X, Y, and Z subgroups + were identified, as was a highly unusual grain with an extreme 30Si + enrichment, a modest 29Si enrichment, and isotopically light C. The + stellar source responsible for this grain is likely to have been a + supernova. Minor differences in isotopic distributions between the + present work and prior data can be partially explained by + terrestrial contamination and grain aggregation on sample mounts, + though some of the differences are probably intrinsic to the + samples. We use the large new SiC database to explore the + relationships between three previously identified isotopic + subgroups---mainstream, Y, and Z grains---all believed to originate + in asymptotic giant branch stars. The isotopic data for Z grains + suggest that their parent stars experienced strong CNO-cycle + nucleosynthesis during the early asymptotic giant branch phase, + consistent with either cool bottom processing in low-mass (M {$<$} + 2.3M{$\odot$}) parent stars or hot-bottom burning in + intermediate-mass stars (M {$>$} 4M{$\odot$}). The data provide + evidence for a sharp threshold in metallicity, above which SiC + grains form with much higher 12C/13C ratios than below. Above this + threshold, the fraction of grains with relatively high 12C/13C + decreases exponentially with increasing 29Si/28Si ratio. This + result indicates a sharp increase in the maximum mass of SiC parent + stars with decreasing metallicity, in contrast to expectations from + Galactic chemical evolution theory.}, + langid = {english}, } @article{SiC-2003-SAV-0, - title = {Barium Isotopes in Individual Presolar Silicon Carbide Grains from the {{Murchison}} Meteorite}, - author = {Savina, Michael R. and Davis, Andrew M. and Tripa, C. Emil and Pellin, Michael J. and Clayton, Robert N. and Lewis, Roy S. and Amari, Sachiko and Gallino, Roberto and Lugaro, Maria}, - year = {2003}, + title = {Barium Isotopes in Individual Presolar Silicon Carbide Grains from + the {{Murchison}} Meteorite}, + author = {Savina, Michael R. and Davis, Andrew M. and Tripa, C. Emil and + Pellin, Michael J. and Clayton, Robert N. and Lewis, Roy S. and Amari + , Sachiko and Gallino, Roberto and Lugaro, Maria}, + year = 2003, month = sep, journal = {Geochimica et Cosmochimica Acta}, series = {A {{Special Issue Dedicated}} to {{Robert Clayton}}}, @@ -934,28 +1982,48 @@ @article{SiC-2003-SAV-0 issn = {0016-7037}, doi = {10.1016/S0016-7037(03)00083-8}, urldate = {2023-01-27}, - abstract = {Barium isotopic compositions of single 2.3--5.3 {$\mu$}m presolar SiC grains from the Murchison meteorite were measured by resonant ionization mass spectrometry. Mainstream SiC grains are enriched in s-process barium and show a spread in isotopic composition from solar to dominantly s-process. In the relatively coarse grain size fraction analyzed, there are large grain-to-grain variations of barium isotopic composition. Comparison of single grain data with models of nucleosynthesis in asymptotic giant branch (AGB) stars indicates that the grains most likely come from low mass carbon-rich AGB stars (1.5 to 3 solar masses) of about solar metallicity and with approximately solar initial proportions of r- and s-process isotopes. Measurements of single grains imply a wide variety of neutron-to-seed ratios, in agreement with previous measurements of strontium, zirconium and molybdenum isotopic compositions of single presolar SiC grains.}, - langid = {english} + abstract = {Barium isotopic compositions of single 2.3--5.3 {$\mu$}m presolar + SiC grains from the Murchison meteorite were measured by resonant + ionization mass spectrometry. Mainstream SiC grains are enriched in + s-process barium and show a spread in isotopic composition from + solar to dominantly s-process. In the relatively coarse grain size + fraction analyzed, there are large grain-to-grain variations of + barium isotopic composition. Comparison of single grain data with + models of nucleosynthesis in asymptotic giant branch (AGB) stars + indicates that the grains most likely come from low mass + carbon-rich AGB stars (1.5 to 3 solar masses) of about solar + metallicity and with approximately solar initial proportions of r- + and s-process isotopes. Measurements of single grains imply a wide + variety of neutron-to-seed ratios, in agreement with previous + measurements of strontium, zirconium and molybdenum isotopic + compositions of single presolar SiC grains.}, + langid = {english}, } @inproceedings{SiC-2004-MAR-0, - title = {A {{NanoSIMS}} Study of Iron-Isotopic Compositions in Presolar Silicon Carbide Grains}, + title = {A {{NanoSIMS}} Study of Iron-Isotopic Compositions in Presolar + Silicon Carbide Grains}, booktitle = {Lunar and {{Planetary Science Conference}}}, author = {Marhas, K. K. and Hoppe, P. and Besmehn, A.}, - year = {2004}, + year = 2004, month = mar, volume = {35}, pages = {1834}, urldate = {2023-01-30}, - abstract = {We measured Fe-isotopic compositions in 8 presolar SiC grains from the Sahara 97166 enstatite chondrite with the NanoSIMS. Except one X grain, all grains have solar Fe-isotopic compositions within 2 sigma errors.}, - annotation = {ADS Bibcode: 2004LPI....35.1834M} + abstract = {We measured Fe-isotopic compositions in 8 presolar SiC grains from + the Sahara 97166 enstatite chondrite with the NanoSIMS. Except one + X grain, all grains have solar Fe-isotopic compositions within 2 + sigma errors.}, } @article{SiC-2004-SAV-0, - title = {Extinct Technetium in Silicon Carbide Stardust Grains: {{Implications}} for Stellar Nucleosynthesis}, + title = {Extinct Technetium in Silicon Carbide Stardust Grains: {{Implications + }} for Stellar Nucleosynthesis}, shorttitle = {Extinct {{Technetium}} in {{Silicon Carbide Stardust Grains}}}, - author = {Savina, Michael R. and Davis, Andrew M. and Tripa, C. Emil and Pellin, Michael J. and Gallino, Roberto and Lewis, Roy S. and Amari, Sachiko}, - year = {2004}, + author = {Savina, Michael R. and Davis, Andrew M. and Tripa, C. Emil and + Pellin, Michael J. and Gallino, Roberto and Lewis, Roy S. and Amari, + Sachiko}, + year = 2004, month = jan, journal = {Science}, volume = {303}, @@ -964,22 +2032,32 @@ @article{SiC-2004-SAV-0 publisher = {American Association for the Advancement of Science}, doi = {10.1126/science.3030649}, urldate = {2023-01-30}, - abstract = {The isotopic composition of ruthenium (Ru) in individual presolar silicon carbide (SiC) stardust grains bears the signature of s-process nucleosynthesis in asymptotic giant branch stars, plus an anomaly in 99Ru that is explained by the in situ decay of technetium isotope 99Tc in the grains. This finding, coupled with the observation of Tc spectral lines in certain stars, shows that the majority of presolar SiC grains come from low-mass asymptotic giant branch stars, and that the amount of 99Tc produced in such stars is insufficient to have left a detectable 99Ru anomaly in early solar system materials.} + abstract = {The isotopic composition of ruthenium (Ru) in individual presolar + silicon carbide (SiC) stardust grains bears the signature of + s-process nucleosynthesis in asymptotic giant branch stars, plus an + anomaly in 99Ru that is explained by the in situ decay of + technetium isotope 99Tc in the grains. This finding, coupled with + the observation of Tc spectral lines in certain stars, shows that + the majority of presolar SiC grains come from low-mass asymptotic + giant branch stars, and that the amount of 99Tc produced in such + stars is insufficient to have left a detectable 99Ru anomaly in + early solar system materials.}, } @article{SiC-2005-MAR-0, title = {Presolar Grains in the {{Tagish Lake}} Meteorite}, author = {Marhas, K. K. and Hoppe, P.}, - year = {2005}, + year = 2005, journal = {Meteoritics and Planetary Science Supplement}, volume = {40}, - pages = {5184} + pages = {5184}, } @article{SiC-2005-NIT-0, - title = {Are Presolar Silicon Carbide Grains from Novae Actually from Supernovae?}, + title = {Are Presolar Silicon Carbide Grains from Novae Actually from + Supernovae?}, author = {Nittler, Larry R. and Hoppe, Peter}, - year = {2005}, + year = 2005, month = aug, journal = {The Astrophysical Journal}, volume = {631}, @@ -988,32 +2066,48 @@ @article{SiC-2005-NIT-0 issn = {0004-637X}, doi = {10.1086/497029}, urldate = {2023-01-30}, - abstract = {We report Si, C, N, Mg-Al, Ca, and Ti isotopic data for three micron-sized presolar SiC grains from the Murchison meteorite. These grains have very low 12C/13C and 14N/15N ratios, similar to grains for which an origin in classical ONe novae has been previously ascribed. Isotopic signatures in one grain (28Si, 49Ti, and 44Ca excesses and a very high inferred 26Al/27Al ratio) indicate that it in fact formed in a supernova, not a nova. Similarly, a large 47Ti excess in another grain argues against a nova origin. The new data raise the question whether all grains previously attributed to novae might have in fact originated in Type II supernovae. The results also point to coupled synthesis of 13C and 15N in Type II supernovae.}, - langid = {english} + abstract = {We report Si, C, N, Mg-Al, Ca, and Ti isotopic data for three + micron-sized presolar SiC grains from the Murchison meteorite. + These grains have very low 12C/13C and 14N/15N ratios, similar to + grains for which an origin in classical ONe novae has been + previously ascribed. Isotopic signatures in one grain (28Si, 49Ti, + and 44Ca excesses and a very high inferred 26Al/27Al ratio) + indicate that it in fact formed in a supernova, not a nova. + Similarly, a large 47Ti excess in another grain argues against a + nova origin. The new data raise the question whether all grains + previously attributed to novae might have in fact originated in + Type II supernovae. The results also point to coupled synthesis of + 13C and 15N in Type II supernovae.}, + langid = {english}, } @inproceedings{SiC-2006-HYN-0, - title = {A Transmission Electron Microscopy Study of Ultramicrotomed {{SiC-X}} Grains}, + title = {A Transmission Electron Microscopy Study of Ultramicrotomed {{SiC-X}} + Grains}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Hynes, K. M. and Croat, T. K. and Amari, S. and Mertz, A. F. and Bernatowicz, T. J.}, - year = {2006}, + author = {Hynes, K. M. and Croat, T. K. and Amari, S. and Mertz, A. F. and + Bernatowicz, T. J.}, + year = 2006, volume = {37}, - pages = {2202} + pages = {2202}, } @inproceedings{SiC-2006-PEL-0, title = {Heavy Metal Isotopic Anomalies in Supernovae Presolar Grains}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Pellin, M. J. and Savina, M. R. and Calaway, W. F. and Tripa, C. E. and Barzyk, J. G. and Davis, A. M. and Gyngard, F. and Amari, S. and Zinner, E. and Lewis, R. S.}, - year = {2006}, + author = {Pellin, M. J. and Savina, M. R. and Calaway, W. F. and Tripa, C. E. + and Barzyk, J. G. and Davis, A. M. and Gyngard, F. and Amari, S. and + Zinner, E. and Lewis, R. S.}, + year = 2006, volume = {37}, - pages = {2041} + pages = {2041}, } @article{SiC-2006-STA-0, - title = {Circumstellar Aluminum Oxide and Silicon Carbide in Interplanetary Dust Particles}, + title = {Circumstellar Aluminum Oxide and Silicon Carbide in Interplanetary + Dust Particles}, author = {Stadermann, Frank J. and Floss, Christine and Wopenka, Brigitte}, - year = {2006}, + year = 2006, month = dec, journal = {Geochimica et Cosmochimica Acta}, series = {A {{Special Issue Dedicated}} to {{Larry A}}. {{Haskin}}}, @@ -1023,34 +2117,65 @@ @article{SiC-2006-STA-0 issn = {0016-7037}, doi = {10.1016/j.gca.2006.08.025}, urldate = {2023-01-30}, - abstract = {A systematic NanoSIMS isotope imaging study of sub-micrometer phases in interplanetary dust particles (IDPs) has led to the discovery of two presolar grain types that previously were observed only in primitive meteorites. A 350{\texttimes}600nm2 Al2O3 grain has a large 17O enrichment and a slight 18O depletion, as well as a 26Mg excess due to the decay of extinct 26Al. Because of its relatively large size and prominent location within the IDP, this presolar Al2O3 grain is well characterized by SEM-EDX analyses. A second, much smaller presolar grain has a diameter of 150nm and a 13C enrichment of more than 300\%. Isotopic anomalies in C are rarely found in IDPs and the magnitude of this anomaly is unprecedented. This grain also has a 15N-rich composition and its isotopic makeup as well as its secondary ion yields identify it as a SiC grain. The discovery of presolar Al2O3 and SiC in IDPs seamlessly complements earlier notions of interplanetary dust particles as the most primitive extraterrestrial material currently available for laboratory analysis. Both Al2O3 and SiC are common presolar grain types in primitive meteorites, but they appeared conspicuously absent from the presolar grain inventory in interplanetary dust particles, which is dominated by silicate stardust. Not finding these presolar grain types in interplanetary dust would have been difficult to explain. Abundance estimates of the new presolar grain types in IDPs are hampered by limited statistics, but both Al2O3 and SiC are less common than presolar silicates which have been found at relatively high abundances in IDPs. The particle in which these presolar grains have been found belongs to the `isotopically primitive subgroup' of IDPs, yet does not contain any presolar silicates.}, - langid = {english} + abstract = {A systematic NanoSIMS isotope imaging study of sub-micrometer + phases in interplanetary dust particles (IDPs) has led to the + discovery of two presolar grain types that previously were observed + only in primitive meteorites. A 350\texttimes 600nm2 Al2O3 grain + has a large 17O enrichment and a slight 18O depletion, as well as a + 26Mg excess due to the decay of extinct 26Al. Because of its + relatively large size and prominent location within the IDP, this + presolar Al2O3 grain is well characterized by SEM-EDX analyses. A + second, much smaller presolar grain has a diameter of 150nm and a + 13C enrichment of more than 300\%. Isotopic anomalies in C are + rarely found in IDPs and the magnitude of this anomaly is + unprecedented. This grain also has a 15N-rich composition and its + isotopic makeup as well as its secondary ion yields identify it as + a SiC grain. The discovery of presolar Al2O3 and SiC in IDPs + seamlessly complements earlier notions of interplanetary dust + particles as the most primitive extraterrestrial material currently + available for laboratory analysis. Both Al2O3 and SiC are common + presolar grain types in primitive meteorites, but they appeared + conspicuously absent from the presolar grain inventory in + interplanetary dust particles, which is dominated by silicate + stardust. Not finding these presolar grain types in interplanetary + dust would have been difficult to explain. Abundance estimates of + the new presolar grain types in IDPs are hampered by limited + statistics, but both Al2O3 and SiC are less common than presolar + silicates which have been found at relatively high abundances in + IDPs. The particle in which these presolar grains have been found + belongs to the `isotopically primitive subgroup' of IDPs, yet does + not contain any presolar silicates.}, + langid = {english}, } @phdthesis{SiC-2007-BAR-0, title = {Multielement Isotopic Analysis of Presolar Silicon Carbide}, author = {Barzyk, Julia G.}, - year = {2007}, + year = 2007, address = {Chicago, Illinois}, - school = {The University of Chicago} + school = {The University of Chicago}, } @article{SiC-2007-HEC-0, - title = {Presolar {{He}} and {{Ne}} Isotopes in Single Circumstellar {{SiC}} Grains}, - author = {Heck, Philipp R. and Marhas, Kuljeet K. and Hoppe, Peter and Gallino, Roberto and Baur, Heinrich and Wieler, Rainer}, - year = {2007}, + title = {Presolar {{He}} and {{Ne}} Isotopes in Single Circumstellar {{SiC}} + Grains}, + author = {Heck, Philipp R. and Marhas, Kuljeet K. and Hoppe, Peter and Gallino + , Roberto and Baur, Heinrich and Wieler, Rainer}, + year = 2007, journal = {The Astrophysical Journal}, volume = {656}, number = {2}, pages = {1208}, publisher = {IOP Publishing}, - doi = {10.1086/510478} + doi = {10.1086/510478}, } @article{SiC-2007-HEN-0, - title = {3-{{D}} Elemental and Isotopic Composition of Presolar Silicon Carbides}, - author = {Henkel, Torsten and Stephan, Thomas and Jessberger, Elmar K. and Hoppe, Peter and Strebel, Roger and Amari, Sachiko and Lewis, Roy S.}, - year = {2007}, + title = {3-{{D}} Elemental and Isotopic Composition of Presolar Silicon + Carbides}, + author = {Henkel, Torsten and Stephan, Thomas and Jessberger, Elmar K. and + Hoppe, Peter and Strebel, Roger and Amari, Sachiko and Lewis, Roy S.}, + year = 2007, journal = {Meteoritics \& Planetary Science}, volume = {42}, number = {7-8}, @@ -1058,14 +2183,34 @@ @article{SiC-2007-HEN-0 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2007.tb00564.x}, urldate = {2023-02-10}, - abstract = {Abstract--- Thirteen presolar silicon carbide grains---three of supernova (SN) origin and ten of asymptotic giant branch (AGB) star origin---were examined with time-of-flight-secondary ion mass spectrometry (TOF-SIMS). The grains had been extracted from two different meteorites---Murchison and Tieschitz---using different acid residue methods. At high lateral resolution of {$\sim$}300 nm, isotopic and elemental heterogeneities within the micrometer-sized grains were detected. The trace elemental abundances, when displayed in two-element correlation plots, of Li, Mg, K, and Ca show a clear distinction between the two different meteoritic sources. The different concentrations might be attributed to differences of the host meteorites and/or of extraction methods whereas the stellar source seems to be less decisive. In one SN grain with 26Mg-enrichment from extinct 26Al, the acid treatment, as part of the grain separation procedure, affected the Mg/Al ratio in the outer rim and therefore the inferred initial 26Al/27Al ratio. A second SN grain exhibits a lateral heterogeneity in 26Al/27Al, which either is due to residual Al-rich contamination on the grain surface or to the condensation chemistry in the SN ejecta.}, - langid = {english} + abstract = {Abstract--- Thirteen presolar silicon carbide grains---three of + supernova (SN) origin and ten of asymptotic giant branch (AGB) star + origin---were examined with time-of-flight-secondary ion mass + spectrometry (TOF-SIMS). The grains had been extracted from two + different meteorites---Murchison and Tieschitz---using different + acid residue methods. At high lateral resolution of {$\sim$}300 nm, + isotopic and elemental heterogeneities within the micrometer-sized + grains were detected. The trace elemental abundances, when + displayed in two-element correlation plots, of Li, Mg, K, and Ca + show a clear distinction between the two different meteoritic + sources. The different concentrations might be attributed to + differences of the host meteorites and/or of extraction methods + whereas the stellar source seems to be less decisive. In one SN + grain with 26Mg-enrichment from extinct 26Al, the acid treatment, + as part of the grain separation procedure, affected the Mg/Al ratio + in the outer rim and therefore the inferred initial 26Al/27Al + ratio. A second SN grain exhibits a lateral heterogeneity in + 26Al/27Al, which either is due to residual Al-rich contamination on + the grain surface or to the condensation chemistry in the SN + ejecta.}, + langid = {english}, } @article{SiC-2007-LYO-0, - title = {Evidence for Lithium and Boron from Star-Forming Regions Implanted in Presolar {{SiC}} Grains}, + title = {Evidence for Lithium and Boron from Star-Forming Regions Implanted in + Presolar {{SiC}} Grains}, author = {Lyon, I. C. and Tizard, J. M. and Henkel, T.}, - year = {2007}, + year = 2007, journal = {Meteoritics \& Planetary Science}, volume = {42}, number = {3}, @@ -1073,14 +2218,40 @@ @article{SiC-2007-LYO-0 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2007.tb00240.x}, urldate = {2023-02-10}, - abstract = {Abstract--- We report the first measurements of lithium and boron isotope ratios and abundances measured in ``gently separated'' presolar SiC grains. Almost all analyses of presolar SiC grains since their first isolation in 1987 have been obtained from grains that were separated from their host meteorite by harsh acid dissolution. We recently reported a new method of ``gently'' separating the grains from meteorites by using freeze-thaw disaggregation, size, and density separation to retain any nonrefractory coatings or alteration to the surfaces of the grains that have been acquired in interstellar space. Nonrefractory coats or amorphized surfaces will almost certainly be removed or altered by the traditional acid separation procedure. High Li/Si and B/Si ratios of up to {$\sim$}10-2 were found implanted in the outer 0.5 {$\mu$}m of the grains dropping to {$\sim$}10-5 in the core of the grains. 7Li/6Li and 11B/10B ratios indistinguishable from solar system average values were found. Analyses obtained from SiC grains from the acid dissolution technique showed isotope ratios that were the same as those of gently separated grains, but depth profiles that were different. These results are interpreted as evidence of implantation of high velocity (1200--1800 km s-1) Li and B ions into the grains by shock waves as the grains traveled through star-forming regions some time after their condensation in the outflow of an AGB star that was their progenitor. The results are in line with spectroscopic measurements of Li and B isotope ratios in star-forming regions and may be used to infer abundances and isotopic sources in these regions.}, - langid = {english} + abstract = {Abstract--- We report the first measurements of lithium and boron + isotope ratios and abundances measured in ``gently separated'' + presolar SiC grains. Almost all analyses of presolar SiC grains + since their first isolation in 1987 have been obtained from grains + that were separated from their host meteorite by harsh acid + dissolution. We recently reported a new method of ``gently'' + separating the grains from meteorites by using freeze-thaw + disaggregation, size, and density separation to retain any + nonrefractory coatings or alteration to the surfaces of the grains + that have been acquired in interstellar space. Nonrefractory coats + or amorphized surfaces will almost certainly be removed or altered + by the traditional acid separation procedure. High Li/Si and B/Si + ratios of up to {$\sim$}10-2 were found implanted in the outer 0.5 + {$\mu$}m of the grains dropping to {$\sim$}10-5 in the core of the + grains. 7Li/6Li and 11B/10B ratios indistinguishable from solar + system average values were found. Analyses obtained from SiC grains + from the acid dissolution technique showed isotope ratios that were + the same as those of gently separated grains, but depth profiles + that were different. These results are interpreted as evidence of + implantation of high velocity (1200--1800 km s-1) Li and B ions + into the grains by shock waves as the grains traveled through + star-forming regions some time after their condensation in the + outflow of an AGB star that was their progenitor. The results are + in line with spectroscopic measurements of Li and B isotope ratios + in star-forming regions and may be used to infer abundances and + isotopic sources in these regions.}, + langid = {english}, } @article{SiC-2007-MAR-0, - title = {{{NanoSIMS}} Studies of {{Ba}} Isotopic Compositions in Single Presolar Silicon Carbide Grains from {{AGB}} Stars and Supernovae}, + title = {{{NanoSIMS}} Studies of {{Ba}} Isotopic Compositions in Single + Presolar Silicon Carbide Grains from {{AGB}} Stars and Supernovae}, author = {Marhas, K. K. and Hoppe, P. and Ott, U.}, - year = {2007}, + year = 2007, journal = {Meteoritics \& Planetary Science}, volume = {42}, number = {7-8}, @@ -1088,15 +2259,48 @@ @article{SiC-2007-MAR-0 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2007.tb00562.x}, urldate = {2023-02-10}, - abstract = {Abstract--- We have studied 74 single presolar silicon carbide grains with sizes between 0.2 and 2.6 {$\mu$}m from the Murchison and Murray meteorites for Ba isotopic compositions using NanoSIMS. We also analyzed 7 SiC particles either consisting of sub-micron-size SiC grains or representing a morphologically and isotopically distinct subgroup. Of the 55 (likely) mainstream grains, originating from asymptotic giant branch (AGB) stars, 32 had high enough Ba contents for isotopic analysis. For 26 of them, CsHx interferences were either negligible or could be corrected with confidence. They exhibit typical s-process Ba isotopic patterns with slightly higher than solar 134Ba/136Ba and lower than solar 135,137,138Ba/136Ba ratios. Results are generally well explained in the context of neutron capture nucleosynthesis in low mass (1--3 M{$\odot$}) AGB stars and provide constraints on AGB models, by reducing the needed 13C spread from factor of {$\sim$}20 down to 2. Out of the 19 supernova X grains, three had sufficient concentrations for isotopic analysis. They tend to exhibit higher than solar 134Ba/136Ba and 138Ba/136Ba ratios, close to solar 137Ba/136Ba, and 135Ba/136Ba lower than solar but higher than in mainstream grains. This signature could indicate a mixture of n-burst type Ba with either ``normal Ba'' more s-process-rich than solar, or normal Ba plus weak s-process Ba. In the n-burst component Cs may have to be separated from Ba at {$\sim$}10 years after the SN explosion. Depending on predictions for its composition, another possibility is early separation (at {$\sim$}1 year) coupled with addition of some unfractionated n-burst matter. Abundances of trace elements (Sr, Zr, Cs, La, and Ce) analyzed along with Ba signify that implantation may have been an important process for their introduction.}, - langid = {english} + abstract = {Abstract--- We have studied 74 single presolar silicon carbide + grains with sizes between 0.2 and 2.6 {$\mu$}m from the Murchison + and Murray meteorites for Ba isotopic compositions using NanoSIMS. + We also analyzed 7 SiC particles either consisting of + sub-micron-size SiC grains or representing a morphologically and + isotopically distinct subgroup. Of the 55 (likely) mainstream + grains, originating from asymptotic giant branch (AGB) stars, 32 + had high enough Ba contents for isotopic analysis. For 26 of them, + CsHx interferences were either negligible or could be corrected + with confidence. They exhibit typical s-process Ba isotopic + patterns with slightly higher than solar 134Ba/136Ba and lower than + solar 135,137,138Ba/136Ba ratios. Results are generally well + explained in the context of neutron capture nucleosynthesis in low + mass (1--3 M{$\odot$}) AGB stars and provide constraints on AGB + models, by reducing the needed 13C spread from factor of {$\sim$}20 + down to 2. Out of the 19 supernova X grains, three had sufficient + concentrations for isotopic analysis. They tend to exhibit higher + than solar 134Ba/136Ba and 138Ba/136Ba ratios, close to solar + 137Ba/136Ba, and 135Ba/136Ba lower than solar but higher than in + mainstream grains. This signature could indicate a mixture of + n-burst type Ba with either ``normal Ba'' more s-process-rich than + solar, or normal Ba plus weak s-process Ba. In the n-burst + component Cs may have to be separated from Ba at {$\sim$}10 years + after the SN explosion. Depending on predictions for its + composition, another possibility is early separation (at {$\sim$}1 + year) coupled with addition of some unfractionated n-burst matter. + Abundances of trace elements (Sr, Zr, Cs, La, and Ce) analyzed + along with Ba signify that implantation may have been an important + process for their introduction.}, + langid = {english}, } @article{SiC-2007-ZIN-0, - title = {{{NanoSIMS}} Isotopic Analysis of Small Presolar Grains: {{Search}} for {{Si}}{\textsubscript{3}}{{N}}{\textsubscript{4}} Grains from {{AGB}} Stars and {{Al}} and {{Ti}} Isotopic Compositions of Rare Presolar {{SiC}} Grains}, + title = {{{NanoSIMS}} Isotopic Analysis of Small Presolar Grains: {{Search}} + for {{Si}}{$_{3}$}{{N}}{$_4$} Grains from {{AGB}} Stars and {{Al}} and + {{Ti}} Isotopic Compositions of Rare Presolar {{SiC}} Grains}, shorttitle = {{{NanoSIMS}} Isotopic Analysis of Small Presolar Grains}, - author = {Zinner, Ernst and Amari, Sachiko and Guinness, Robert and Jennings, Cristine and Mertz, Aaron F. and Nguyen, Ann N. and Gallino, Roberto and Hoppe, Peter and Lugaro, Maria and Nittler, Larry R. and Lewis, Roy S.}, - year = {2007}, + author = {Zinner, Ernst and Amari, Sachiko and Guinness, Robert and Jennings, + Cristine and Mertz, Aaron F. and Nguyen, Ann N. and Gallino, Roberto + and Hoppe, Peter and Lugaro, Maria and Nittler, Larry R. and Lewis, + Roy S.}, + year = 2007, month = oct, journal = {Geochimica et Cosmochimica Acta}, volume = {71}, @@ -1105,26 +2309,71 @@ @article{SiC-2007-ZIN-0 issn = {0016-7037}, doi = {10.1016/j.gca.2007.07.012}, urldate = {2023-02-10}, - abstract = {We report isotopic ratio measurements of small SiC and Si3N4 grains, with special emphasis on presolar SiC grains of type Z, and new nucleosynthesis models for 26Al/27Al and the Ti isotopic ratios in asymptotic giant branch (AGB) stars. With the NanoSIMS we analyzed 310 SiC grains from Murchison (carbonaceous CM2 chondrite) separate KJB (diameters 0.25--0.45{$\mu$}m) and 153 SiC grains from KJG (diameters 1.8--3.7{$\mu$}m), 154 SiC and 23 Si3N4 grains from Indarch (enstatite EH4 chondrite) separate IH6 (diameters 0.25--0.65{$\mu$}m) for their C and N isotopic compositions, 549 SiC and 142 Si3N4 grains from IH6 for their C and Si isotopic compositions, 13 SiC grains from Murchison and 66 from Indarch for their Al--Mg compositions, and eight SiC grains from Murchison and 10 from Indarch for their Ti isotopic compositions. One of the original objectives of this effort was to compare isotopic analyses with the NanoSIMS with analyses previously obtained with the Cameca IMS 3f ion microprobe. Many of the Si3N4 grains from Indarch have isotopic anomalies but most of these apparently originate from adjacent SiC grains. Only one Si3N4 grain, with 13C and 14N excesses, has a likely AGB origin. The C, N, and Si isotopic data show that the percentage of SiC grains of type Y and Z increase with decreasing grain size (from {$\sim$}1\% for grains {$>$}2{$\mu$}m to {$\sim$}5--7\% for grains of 0.5{$\mu$}m), providing an opportunity for isotopic analyses in these rare grains. Our measurements expand the number of Al--Mg analyses on SiC Z grains from 4 to 23 and the number of Ti analyses on Z grains from 2 to 11. Inferred26Al/27Al ratios of Z grains are in the range found in mainstream and Y grains and do not exceed those predicted by models of AGB nucleosynthesis. Cool bottom processing (CBP) has been invoked to explain the low 12C/13C ratios of Z grains, but this process apparently does not lead to increased 26Al production in the parent stars of these grains. This finding is in contrast to presolar oxide grains where CBP is needed to explain their high 26Al/27Al ratios. The low 46,47,49Ti/48Ti ratios found in Z grains and their correlation with low 29Si/28Si ratios extend the trend seen in mainstream grains and confirm an origin in low-metallicity AGB stars. The relatively large excesses in 30Si and 50Ti in Z grains are predicted by our models to be the result of increased production of these isotopes by neutron-capture nucleosynthesis in low-metallicity AGB stars. However, the predicted excesses in 50Ti (and 49Ti) are much larger than those found. Even lowering the strength of the 13C pocket cannot solve this discrepancy in a consistent way.}, - langid = {english} + abstract = {We report isotopic ratio measurements of small SiC and Si3N4 + grains, with special emphasis on presolar SiC grains of type Z, and + new nucleosynthesis models for 26Al/27Al and the Ti isotopic ratios + in asymptotic giant branch (AGB) stars. With the NanoSIMS we + analyzed 310 SiC grains from Murchison (carbonaceous CM2 chondrite) + separate KJB (diameters 0.25--0.45{$\mu$}m) and 153 SiC grains from + KJG (diameters 1.8--3.7{$\mu$}m), 154 SiC and 23 Si3N4 grains from + Indarch (enstatite EH4 chondrite) separate IH6 (diameters + 0.25--0.65{$\mu$}m) for their C and N isotopic compositions, 549 + SiC and 142 Si3N4 grains from IH6 for their C and Si isotopic + compositions, 13 SiC grains from Murchison and 66 from Indarch for + their Al--Mg compositions, and eight SiC grains from Murchison and + 10 from Indarch for their Ti isotopic compositions. One of the + original objectives of this effort was to compare isotopic analyses + with the NanoSIMS with analyses previously obtained with the Cameca + IMS 3f ion microprobe. Many of the Si3N4 grains from Indarch have + isotopic anomalies but most of these apparently originate from + adjacent SiC grains. Only one Si3N4 grain, with 13C and 14N + excesses, has a likely AGB origin. The C, N, and Si isotopic data + show that the percentage of SiC grains of type Y and Z increase + with decreasing grain size (from {$\sim$}1\% for grains {$>$}2{$\mu + $}m to {$\sim$}5--7\% for grains of 0.5{$\mu$}m), providing an + opportunity for isotopic analyses in these rare grains. Our + measurements expand the number of Al--Mg analyses on SiC Z grains + from 4 to 23 and the number of Ti analyses on Z grains from 2 to + 11. Inferred26Al/27Al ratios of Z grains are in the range found in + mainstream and Y grains and do not exceed those predicted by models + of AGB nucleosynthesis. Cool bottom processing (CBP) has been + invoked to explain the low 12C/13C ratios of Z grains, but this + process apparently does not lead to increased 26Al production in + the parent stars of these grains. This finding is in contrast to + presolar oxide grains where CBP is needed to explain their high + 26Al/27Al ratios. The low 46,47,49Ti/48Ti ratios found in Z grains + and their correlation with low 29Si/28Si ratios extend the trend + seen in mainstream grains and confirm an origin in low-metallicity + AGB stars. The relatively large excesses in 30Si and 50Ti in Z + grains are predicted by our models to be the result of increased + production of these isotopes by neutron-capture nucleosynthesis in + low-metallicity AGB stars. However, the predicted excesses in 50Ti + (and 49Ti) are much larger than those found. Even lowering the + strength of the 13C pocket cannot solve this discrepancy in a + consistent way.}, + langid = {english}, } @inproceedings{SiC-2008-HYN-0, title = {Continued Studies of Ultramicrotomed Presolar {{SiC X}} Grains}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {Hynes, K. M. and Amari, S. and Bernatowicz, T. J. and Croat, T. K. and Mertz, A. F.}, - year = {2008}, + author = {Hynes, K. M. and Amari, S. and Bernatowicz, T. J. and Croat, T. K. + and Mertz, A. F.}, + year = 2008, volume = {39}, pages = {2076}, urldate = {2023-02-10}, - abstract = {We report the results of a coordinated NanoSIMS and TEM study of three SiC X grains. The SN origin of these grains is indicated by their isotopic compositions, their crystal sizes, and the large amount of Mg from the decay of 26Al observed in the grains.}, - annotation = {ADS Bibcode: 2008LPI....39.2076H} + abstract = {We report the results of a coordinated NanoSIMS and TEM study of + three SiC X grains. The SN origin of these grains is indicated by + their isotopic compositions, their crystal sizes, and the large + amount of Mg from the decay of 26Al observed in the grains.}, } @article{SiC-2008-MAR-0, title = {Iron and Nickel Isotopic Ratios in Presolar {{SiC}} Grains}, - author = {Marhas, Kuljeet K. and Amari, Sachiko and Gyngard, Frank and Zinner, Ernst and Gallino, Roberto}, - year = {2008}, + author = {Marhas, Kuljeet K. and Amari, Sachiko and Gyngard, Frank and Zinner, + Ernst and Gallino, Roberto}, + year = 2008, month = dec, journal = {The Astrophysical Journal}, volume = {689}, @@ -1133,14 +2382,38 @@ @article{SiC-2008-MAR-0 issn = {0004-637X}, doi = {10.1086/592599}, urldate = {2023-02-10}, - abstract = {We report the first Fe isotopic anomalies and the first Ni isotopic ratio measurements in presolar SiC grains of separate KJG from the Murchison meteorite. With NanoSIMS, we analyzed Fe and Ni in 37 X grains from Type II supernovae and 53 SiC grains of other types. The Ni/Fe and Co/Fe ratios in grains of all types are much higher than in the gas from which the grains are believed to have condensed. A majority of the X grains and a couple of mainstream grains contain Fe-rich subgrains. Most X grains have large excesses in 57Fe,61Ni, and 62Ni.60Ni excesses are small and the 54Fe/56Fe ratios of almost all X grains are normal. These isotopic compositions are best explained by mixing of material from the He/N zone of Type II supernovae with material from the He/C zone. The lack of any 54Fe excesses is puzzling in view of the fact that the Si/S zone, whose contribution resulted in the 28Si excesses in X grains, is very rich in 54Fe. It has yet to be seen whether elemental fractionation between Si and Fe is an explanation. The 57Fe deficits observed in a few X grains remain unexplained. In comparison to the X grains, fewer mainstream and AB grains have anomalies. Observed 62Ni excesses in some mainstream grains are larger than predicted for AGB stars of solar metallicity and are not accompanied by corresponding 61Ni excesses. A Y grain and a Z grain have excesses in 54Fe and 62Ni, but close to normal 57Fe/56Fe and 60,61Ni/58Ni ratios. These isotopic compositions are not expected for grains from low-metallicity AGB stars.}, - langid = {english} + abstract = {We report the first Fe isotopic anomalies and the first Ni + isotopic ratio measurements in presolar SiC grains of separate KJG + from the Murchison meteorite. With NanoSIMS, we analyzed Fe and Ni + in 37 X grains from Type II supernovae and 53 SiC grains of other + types. The Ni/Fe and Co/Fe ratios in grains of all types are much + higher than in the gas from which the grains are believed to have + condensed. A majority of the X grains and a couple of mainstream + grains contain Fe-rich subgrains. Most X grains have large excesses + in 57Fe,61Ni, and 62Ni.60Ni excesses are small and the 54Fe/56Fe + ratios of almost all X grains are normal. These isotopic + compositions are best explained by mixing of material from the He/N + zone of Type II supernovae with material from the He/C zone. The + lack of any 54Fe excesses is puzzling in view of the fact that the + Si/S zone, whose contribution resulted in the 28Si excesses in X + grains, is very rich in 54Fe. It has yet to be seen whether + elemental fractionation between Si and Fe is an explanation. The + 57Fe deficits observed in a few X grains remain unexplained. In + comparison to the X grains, fewer mainstream and AB grains have + anomalies. Observed 62Ni excesses in some mainstream grains are + larger than predicted for AGB stars of solar metallicity and are + not accompanied by corresponding 61Ni excesses. A Y grain and a Z + grain have excesses in 54Fe and 62Ni, but close to normal 57Fe/56Fe + and 60,61Ni/58Ni ratios. These isotopic compositions are not + expected for grains from low-metallicity AGB stars.}, + langid = {english}, } @article{SiC-2008-YAD-0, title = {Stardust in {{Antarctic}} Micrometeorites}, - author = {Yada, Toru and Floss, Christine and Stadermann, Frank J. and Zinner, Ernst and Nakamura, Tomoki and Noguchi, Takaaki and Lea, A. Scott}, - year = {2008}, + author = {Yada, Toru and Floss, Christine and Stadermann, Frank J. and Zinner, + Ernst and Nakamura, Tomoki and Noguchi, Takaaki and Lea, A. Scott}, + year = 2008, journal = {Meteoritics \& Planetary Science}, volume = {43}, number = {8}, @@ -1148,14 +2421,38 @@ @article{SiC-2008-YAD-0 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2008.tb00698.x}, urldate = {2023-02-10}, - abstract = {Abstract--- We report the discovery of presolar silicate, oxide (hibonite), and (possibly) SiC grains in four Antarctic micrometeorites (AMMs). The oxygen isotopic compositions of the eighteen presolar silicate (and one oxide) grains found are similar those observed previously in primitive meteorites and interplanetary dust particles, and indicate origins in oxygen-rich red giant or asymptotic giant branch stars, or in supernovae. Four grains with anomalous C isotopic compositions were also detected. 12C/13C as well as Si ratios are similar to those of mainstream SiC grains; the N isotopic composition of one grain is also consistent with a mainstream SiC classification. Presolar silicate grains were found in three of the seven AMMs studied, and are heterogeneously distributed within these micrometeorites. Fourteen of the 18 presolar silicate grains and 3 of the 4 C-anomalous grains were found within one AMM, T98G8. Presolar silicate-bearing micrometeorites contain crystalline silicates that give sharp X-ray diffractions and do not contain magnesiow{\"u}stite, which forms mainly through the decomposition of phyllosilicates and carbonates. The occurrence of this mineral in AMMs without presolar silicates suggests that secondary parent body processes probably determine the presence or absence of presolar silicates in Antarctic micrometeorites.}, - langid = {english} + abstract = {Abstract--- We report the discovery of presolar silicate, oxide + (hibonite), and (possibly) SiC grains in four Antarctic + micrometeorites (AMMs). The oxygen isotopic compositions of the + eighteen presolar silicate (and one oxide) grains found are similar + those observed previously in primitive meteorites and + interplanetary dust particles, and indicate origins in oxygen-rich + red giant or asymptotic giant branch stars, or in supernovae. Four + grains with anomalous C isotopic compositions were also detected. + 12C/13C as well as Si ratios are similar to those of mainstream SiC + grains; the N isotopic composition of one grain is also consistent + with a mainstream SiC classification. Presolar silicate grains were + found in three of the seven AMMs studied, and are heterogeneously + distributed within these micrometeorites. Fourteen of the 18 + presolar silicate grains and 3 of the 4 C-anomalous grains were + found within one AMM, T98G8. Presolar silicate-bearing + micrometeorites contain crystalline silicates that give sharp X-ray + diffractions and do not contain magnesiow\"ustite, which forms + mainly through the decomposition of phyllosilicates and carbonates. + The occurrence of this mineral in AMMs without presolar silicates + suggests that secondary parent body processes probably determine + the presence or absence of presolar silicates in Antarctic + micrometeorites.}, + langid = {english}, } @article{SiC-2009-BUS-0, - title = {Ultra-Primitive Interplanetary Dust Particles from the Comet {{26P}}/{{Grigg}}--{{Skjellerup}} Dust Stream Collection}, - author = {Busemann, Henner and Nguyen, Ann N. and Cody, George D. and Hoppe, Peter and Kilcoyne, A. L. David and Stroud, Rhonda M. and Zega, Thomas J. and Nittler, Larry R.}, - year = {2009}, + title = {Ultra-Primitive Interplanetary Dust Particles from the Comet {{26P}}/ + {{Grigg}}--{{Skjellerup}} Dust Stream Collection}, + author = {Busemann, Henner and Nguyen, Ann N. and Cody, George D. and Hoppe, + Peter and Kilcoyne, A. L. David and Stroud, Rhonda M. and Zega, + Thomas J. and Nittler, Larry R.}, + year = 2009, month = oct, journal = {Earth and Planetary Science Letters}, volume = {288}, @@ -1164,15 +2461,54 @@ @article{SiC-2009-BUS-0 issn = {0012-821X}, doi = {10.1016/j.epsl.2009.09.007}, urldate = {2023-02-10}, - abstract = {Cometary material and pristine interplanetary dust particles (IDPs) best resemble the unaltered components from which our solar system was built because they have remained largely unaltered in a cold undisturbed environment since accretion in the outer protoplanetary disk. IDPs might supply more primitive assemblages for laboratory analysis than Stardust samples from comet 81P/Wild 2 but their individual provenances are typically unknown. We speculate that some IDPs collected by NASA in April 2003 may be associated with comet 26P/Grigg--Skjellerup because their particularly pristine character coincides with the collection period that was predicted to show an enhanced flux of particles from this Jupiter-family comet. Some IDPs from this collection contain the most primitive assembly of interstellar matter found to date including an unusually high abundance of presolar grains and very isotopically anomalous and disordered organic matter as well as fine-grained carbonates and an amphibole associated with a GEMS-like object (glass with embedded metals and sulfides) that potentially imply formation in a nebular rather than planetary environment. The two most primitive IDPs may contain assemblages of molecular cloud material at the percent level which is supported by the presence of four rare 17O-depleted presolar silicate grains possibly of supernova(e) origin within one {\textasciitilde}70{$\mu$}m2-sized IDP and the close association of a Group 1Mg-rich olivine from a low-mass red giant star with a carbonaceous nano-globule of potentially interstellar origin. Our study together with observations of comet 9P/Tempel 1 during the Deep Impact experiment and 81P/Wild 2 dust analyses reveal some compositional variations and many similarities among three Jupiter-family comets. Specifically carbonates and primitive organic matter or amorphous carbon were widespread in the comet-forming regions of the outer protoplanetary disk and not all comets contain as much inner solar system material as has been inferred for comet 81P/Wild 2. The bulk and hotspot hydrogen and nitrogen isotopic anomalies as well as the carbon Raman characteristics of the organic matter in IDPs and the most primitive meteorites are remarkably similar. This implies that the same mixture of molecular cloud material had been transported inward into the meteorite-forming regions of the solar system.}, + abstract = {Cometary material and pristine interplanetary dust particles + (IDPs) best resemble the unaltered components from which our solar + system was built because they have remained largely unaltered in a + cold undisturbed environment since accretion in the outer + protoplanetary disk. IDPs might supply more primitive assemblages + for laboratory analysis than Stardust samples from comet 81P/Wild 2 + but their individual provenances are typically unknown. We + speculate that some IDPs collected by NASA in April 2003 may be + associated with comet 26P/Grigg--Skjellerup because their + particularly pristine character coincides with the collection + period that was predicted to show an enhanced flux of particles + from this Jupiter-family comet. Some IDPs from this collection + contain the most primitive assembly of interstellar matter found to + date including an unusually high abundance of presolar grains and + very isotopically anomalous and disordered organic matter as well + as fine-grained carbonates and an amphibole associated with a + GEMS-like object (glass with embedded metals and sulfides) that + potentially imply formation in a nebular rather than planetary + environment. The two most primitive IDPs may contain assemblages of + molecular cloud material at the percent level which is supported by + the presence of four rare 17O-depleted presolar silicate grains + possibly of supernova(e) origin within one \textasciitilde 70{$\mu$ + }m2-sized IDP and the close association of a Group 1Mg-rich olivine + from a low-mass red giant star with a carbonaceous nano-globule of + potentially interstellar origin. Our study together with + observations of comet 9P/Tempel 1 during the Deep Impact experiment + and 81P/Wild 2 dust analyses reveal some compositional variations + and many similarities among three Jupiter-family comets. + Specifically carbonates and primitive organic matter or amorphous + carbon were widespread in the comet-forming regions of the outer + protoplanetary disk and not all comets contain as much inner solar + system material as has been inferred for comet 81P/Wild 2. The bulk + and hotspot hydrogen and nitrogen isotopic anomalies as well as the + carbon Raman characteristics of the organic matter in IDPs and the + most primitive meteorites are remarkably similar. This implies that + the same mixture of molecular cloud material had been transported + inward into the meteorite-forming regions of the solar system.}, langid = {english}, - keywords = {comet Grigg-Skjellerup,interplanetary dust particles,interstellar medium,organic matter,presolar grains,solar system formation} + keywords = {comet Grigg-Skjellerup,interplanetary dust particles,interstellar + medium,organic matter,presolar grains,solar system formation}, } @article{SiC-2009-FLO-0, - title = {High Abundances of Circumstellar and Interstellar {{C-anomalous}} Phases in the Primitive {{CR3}} Chondrites {{QUE}} 99177 and {{MET}} 00426}, + title = {High Abundances of Circumstellar and Interstellar {{C-anomalous}} + Phases in the Primitive {{CR3}} Chondrites {{QUE}} 99177 and {{MET}} + 00426}, author = {Floss, Christine and Stadermann, Frank J.}, - year = {2009}, + year = 2009, month = may, journal = {The Astrophysical Journal}, volume = {697}, @@ -1182,14 +2518,32 @@ @article{SiC-2009-FLO-0 issn = {0004-637X}, doi = {10.1088/0004-637X/697/2/1242}, urldate = {2023-02-10}, - abstract = {QUE 99177 and MET 00426 are the first known CR3 chondrites and have largely escaped the aqueous alteration experienced by most of the CR chondrite group. In addition to high presolar silicate and oxide grain abundances, these meteorites also contain high abundances of phases with anomalous C isotopic compositions. Presolar SiC abundances ({$\sim$}65 ppm) are consistent with independent estimates for CR1 and CR2 chondrites, indicating that aqueous alteration does not destroy SiC, but are significantly higher than earlier abundance estimates based on noble gas contents. Particularly notable are the high abundances ({$\sim$}120 ppm) of carbonaceous matter with anomalous C isotopic compositions that probably formed in cold molecular clouds via ion--molecule reactions. The observation of both 13C-enriched and 13C-depleted compositions suggests that multiple chemical pathways contribute to the formation of this material. The abundance of such material is significantly higher in QUE 99177 and MET 00426 than in other primitive meteorites and attests to the primitive nature of the CR3 chondrites.}, - langid = {english} + abstract = {QUE 99177 and MET 00426 are the first known CR3 chondrites and + have largely escaped the aqueous alteration experienced by most of + the CR chondrite group. In addition to high presolar silicate and + oxide grain abundances, these meteorites also contain high + abundances of phases with anomalous C isotopic compositions. + Presolar SiC abundances ({$\sim$}65 ppm) are consistent with + independent estimates for CR1 and CR2 chondrites, indicating that + aqueous alteration does not destroy SiC, but are significantly + higher than earlier abundance estimates based on noble gas + contents. Particularly notable are the high abundances ({$\sim$}120 + ppm) of carbonaceous matter with anomalous C isotopic compositions + that probably formed in cold molecular clouds via ion--molecule + reactions. The observation of both 13C-enriched and 13C-depleted + compositions suggests that multiple chemical pathways contribute to + the formation of this material. The abundance of such material is + significantly higher in QUE 99177 and MET 00426 than in other + primitive meteorites and attests to the primitive nature of the CR3 + chondrites.}, + langid = {english}, } @article{SiC-2009-GYN-0, - title = {Interstellar Exposure Ages of Large Presolar {{SiC}} Grains from the {{Murchison}} Meteorite}, + title = {Interstellar Exposure Ages of Large Presolar {{SiC}} Grains from the + {{Murchison}} Meteorite}, author = {Gyngard, Frank and Amari, Sachiko and Zinner, Ernst and Ott, Ulrich}, - year = {2009}, + year = 2009, month = mar, journal = {The Astrophysical Journal}, volume = {694}, @@ -1199,14 +2553,35 @@ @article{SiC-2009-GYN-0 issn = {0004-637X}, doi = {10.1088/0004-637X/694/1/359}, urldate = {2023-02-10}, - abstract = {We report the Li isotopic compositions of nine large, greater than 5 {$\mu$}m, presolar SiC grains from the Murchison (CM) meteorite. Most of the SiC grains analyzed are isotopically similar in C and Si and morphologically distinct from other presolar SiC grains. Their 7Li/6Li ratios range from {$\sim$}9.3 to the solar value ({$\sim$}12). The 6Li enrichments observed in the grains can only arise from galactic cosmic ray spallation off C atoms during travel through the interstellar medium (ISM) and before incorporation into the meteorite parent body. Using appropriate production rates, we calculate recoil-loss-corrected individual exposure ages of eight grains with 6Li excesses that range from 40 Myr to about 1 Gyr. The long exposure ages ({$>$}500 Myr) are consistent with calculations of grain survival lifetimes in the ISM, while the shorter ages ({$<$}100 Myr) of two grains are more consistent with previous cosmogenic noble gas studies. Although the sample size is only eight grains, there appears to be little evidence for clustering of exposure ages and no obvious correlation between exposure age and grain size.}, - langid = {english} + abstract = {We report the Li isotopic compositions of nine large, greater than + 5 {$\mu$}m, presolar SiC grains from the Murchison (CM) meteorite. + Most of the SiC grains analyzed are isotopically similar in C and + Si and morphologically distinct from other presolar SiC grains. + Their 7Li/6Li ratios range from {$\sim$}9.3 to the solar value ({$ + \sim$}12). The 6Li enrichments observed in the grains can only + arise from galactic cosmic ray spallation off C atoms during travel + through the interstellar medium (ISM) and before incorporation into + the meteorite parent body. Using appropriate production rates, we + calculate recoil-loss-corrected individual exposure ages of eight + grains with 6Li excesses that range from 40 Myr to about 1 Gyr. The + long exposure ages ({$>$}500 Myr) are consistent with calculations + of grain survival lifetimes in the ISM, while the shorter ages ( { + $<$}100 Myr) of two grains are more consistent with previous + cosmogenic noble gas studies. Although the sample size is only + eight grains, there appears to be little evidence for clustering of + exposure ages and no obvious correlation between exposure age and + grain size.}, + langid = {english}, } @article{SiC-2009-HEC-0, - title = {Interstellar Residence Times of Presolar {{SiC}} Dust Grains from the {{Murchison}} Carbonaceous Meteorite}, - author = {Heck, Philipp R. and Gyngard, Frank and Ott, Ulrich and Meier, Matthias M. M. and {\'A}vila, Jana{\'i}na N. and Amari, Sachiko and Zinner, Ernst K. and Lewis, Roy S. and Baur, Heinrich and Wieler, Rainer}, - year = {2009}, + title = {Interstellar Residence Times of Presolar {{SiC}} Dust Grains from the + {{Murchison}} Carbonaceous Meteorite}, + author = {Heck, Philipp R. and Gyngard, Frank and Ott, Ulrich and Meier, + Matthias M. M. and {\'A}vila, Jana{\'i}na N. and Amari, Sachiko and + Zinner, Ernst K. and Lewis, Roy S. and Baur, Heinrich and Wieler, + Rainer}, + year = 2009, month = may, journal = {The Astrophysical Journal}, volume = {698}, @@ -1216,15 +2591,34 @@ @article{SiC-2009-HEC-0 issn = {0004-637X}, doi = {10.1088/0004-637X/698/2/1155}, urldate = {2023-02-10}, - abstract = {The time span between the formation of presolar grains in stellar outflows and their incorporation into early solar-system solids is poorly constrained. Knowledge of this time span is essential for a better understanding of the processing of grains in the interstellar medium (ISM) and formation processes of the solar system. Here, we report interstellar residence times of {$\sim$}3--1100 Myr for large ({$\sim$}5--50 {$\mu$}m) presolar SiC grains, based on their content of He and Ne produced by Galactic cosmic rays. A majority of these grains have interstellar residence times on the order of a few tens up to less than 200 Myr, considerably shorter than theoretical estimates of interstellar dust lifetimes ({$\sim$}500 Myr), but long enough to require formation of the majority of the grains before that of the presolar molecular cloud. The age distribution may be explained by starburst activity 1--2 billion years prior to the birth of the Sun. Our findings provide essential ``ground truth'' to constrain models of interstellar dust lifetimes and destructive processes in the ISM.}, - langid = {english} + abstract = {The time span between the formation of presolar grains in stellar + outflows and their incorporation into early solar-system solids is + poorly constrained. Knowledge of this time span is essential for a + better understanding of the processing of grains in the + interstellar medium (ISM) and formation processes of the solar + system. Here, we report interstellar residence times of {$\sim$} + 3--1100 Myr for large ({$\sim$}5--50 {$\mu$}m) presolar SiC grains, + based on their content of He and Ne produced by Galactic cosmic + rays. A majority of these grains have interstellar residence times + on the order of a few tens up to less than 200 Myr, considerably + shorter than theoretical estimates of interstellar dust lifetimes ( + {$\sim$}500 Myr), but long enough to require formation of the + majority of the grains before that of the presolar molecular cloud. + The age distribution may be explained by starburst activity 1--2 + billion years prior to the birth of the Sun. Our findings provide + essential ``ground truth'' to constrain models of interstellar dust + lifetimes and destructive processes in the ISM.}, + langid = {english}, } @article{SiC-2009-HOP-0, - title = {An Unusual Presolar Silicon Carbide Grain from a Supernova: {{Implications}} for the Production of Silicon-29 in Type {{II}} Supernovae}, + title = {An Unusual Presolar Silicon Carbide Grain from a Supernova: {{ + Implications}} for the Production of Silicon-29 in Type {{II}} + Supernovae}, shorttitle = {{{AN UNUSUAL PRESOLAR SILICON CARBIDE GRAIN FROM A SUPERNOVA}}}, - author = {Hoppe, Peter and Leitner, Jan and Meyer, Bradley S. and The, Lih-Sin and Lugaro, Maria and Amari, Sachiko}, - year = {2009}, + author = {Hoppe, Peter and Leitner, Jan and Meyer, Bradley S. and The, Lih-Sin + and Lugaro, Maria and Amari, Sachiko}, + year = 2009, journal = {The Astrophysical Journal}, volume = {691}, number = {1}, @@ -1233,14 +2627,39 @@ @article{SiC-2009-HOP-0 issn = {0004-637X}, doi = {10.1088/0004-637X/691/1/L20}, urldate = {2023-02-10}, - abstract = {We report the discovery of a presolar SiC grain (KJB2-11-17-1) with unusual Si-isotopic composition. The grain has 29Si/28Si = 1.63 {\texttimes} solar, 30Si/28Si = 0.82 {\texttimes} solar, 12C/13C = 265 (= 3 {\texttimes} solar), and evidence for the presence of radiogenic 44Ca from the decay of 44Ti. A comparison of these isotopic signatures with stellar models suggests an origin in a 15 M{$\Sun$} Type II supernova. It is possible to achieve a very good match between the 30Si/28Si, 12C/13C, and inferred 44Ti/48Ti ratios in KJB2-11-17-1 and the model predictions if matter from different supernova zones is mixed in appropriate proportions. The 29Si/28Si ratio, however, cannot be reproduced and is clearly higher than predicted. It was suggested previously by Travaglio et al. that supernova models underestimate the 29Si yield in the C- and Ne-burning regions by about a factor of 2. Because of its very high 29Si/30Si of two times the solar ratio, grain KJB2-11-17-1 provides the opportunity to make a stringent test of this hypothesis. With a twofold enhanced 29Si yield in the C- and Ne-burning zones, we find a perfect match for 29Si/28Si between the model predictions and the grain. Nuclear network calculations show that a twofold increase in the 29Si yield in the C- and Ne-burning regions requires roughly a threefold higher 26Mg({$\alpha$}, n)29Si reaction rate, the most important reaction for the production of 29Si, in the temperature range 1--3 {\texttimes} 109 K than currently used in supernova models. This increase is qualitatively within current uncertainties of this reaction rate.}, - langid = {english} + abstract = {We report the discovery of a presolar SiC grain (KJB2-11-17-1) + with unusual Si-isotopic composition. The grain has 29Si/28Si = + 1.63 \texttimes{} solar, 30Si/28Si = 0.82 \texttimes{} solar, + 12C/13C = 265 (= 3 \texttimes{} solar), and evidence for the + presence of radiogenic 44Ca from the decay of 44Ti. A comparison of + these isotopic signatures with stellar models suggests an origin in + a 15 M{$\Sun$} Type II supernova. It is possible to achieve a very + good match between the 30Si/28Si, 12C/13C, and inferred 44Ti/48Ti + ratios in KJB2-11-17-1 and the model predictions if matter from + different supernova zones is mixed in appropriate proportions. The + 29Si/28Si ratio, however, cannot be reproduced and is clearly + higher than predicted. It was suggested previously by Travaglio et + al. that supernova models underestimate the 29Si yield in the C- + and Ne-burning regions by about a factor of 2. Because of its very + high 29Si/30Si of two times the solar ratio, grain KJB2-11-17-1 + provides the opportunity to make a stringent test of this + hypothesis. With a twofold enhanced 29Si yield in the C- and + Ne-burning zones, we find a perfect match for 29Si/28Si between the + model predictions and the grain. Nuclear network calculations show + that a twofold increase in the 29Si yield in the C- and Ne-burning + regions requires roughly a threefold higher 26Mg({$\alpha$}, n)29Si + reaction rate, the most important reaction for the production of + 29Si, in the temperature range 1--3 \texttimes{} 109 K than + currently used in supernova models. This increase is qualitatively + within current uncertainties of this reaction rate.}, + langid = {english}, } @article{SiC-2010-CRO-0, - title = {Unusual {\textsuperscript{29,30}}{{Si-rich SiCs}} of Massive Star Origin Found within Graphites from the {{Murchison}} Meteorite}, + title = {Unusual {\textsuperscript{29,30}}{{Si-rich SiCs}} of Massive Star + Origin Found within Graphites from the {{Murchison}} Meteorite}, author = {Croat, T. K. and Stadermann, F. J. and Bernatowicz, T. J.}, - year = {2010}, + year = 2010, month = apr, journal = {The Astronomical Journal}, volume = {139}, @@ -1250,27 +2669,53 @@ @article{SiC-2010-CRO-0 issn = {1538-3881}, doi = {10.1088/0004-6256/139/6/2159}, urldate = {2023-02-10}, - abstract = {Correlated transmission electron microscopy and NanoSIMS isotopic studies have revealed two unusual SiCs with large 29,30Si enrichments within micron-sized graphites from the Murchison meteorite. Such anomalies are rare among the overall SiC population (in {$\ll$}0.01\% of SiCs yet measured), whereas two of the three SiCs found within graphite show 29,30Si enrichments, in one case as large as 29Si/28Si = (2.28 {\textpm} 0.03) {\texttimes} solar and 30Si/28Si = (2.03 {\textpm} 0.03){\texttimes} solar. C-burning and Ne-burning in massive stars ({$>$}8 M{$\Sun$} initial mass) during their post-main-sequence development are the only processes capable of producing sufficiently large 29,30Si enrichments. This material with heavy Si isotopic enrichments from the O/Ne and O/Si layers is later incorporated into carbonaceous stardust, either in ejecta from Type II supernovae or perhaps in the colliding winds of Wolf--Rayet binaries. Although often too small for Si isotopic measurements, four other SiC-containing graphites show other signatures of a massive star origin. Abundance estimates suggest that such unusual SiCs are present within {$\sim$}1\% of high-density graphites. This abundance can be reconciled with the much lower abundance in the overall SiC population if these unusual SiCs are naturally smaller ({$\sim$}200 nm or less) than SiCs from other isotopic subgroups and if differential destruction of small unusual SiCs occurs in massive star outflows unless these SiCs are encapsulated in graphite.}, - langid = {english} + abstract = {Correlated transmission electron microscopy and NanoSIMS isotopic + studies have revealed two unusual SiCs with large 29,30Si + enrichments within micron-sized graphites from the Murchison + meteorite. Such anomalies are rare among the overall SiC population + (in {$\ll$}0.01\% of SiCs yet measured), whereas two of the three + SiCs found within graphite show 29,30Si enrichments, in one case as + large as 29Si/28Si = (2.28 \textpm{} 0.03) \texttimes{} solar and + 30Si/28Si = (2.03 \textpm{} 0.03)\texttimes{} solar. C-burning and + Ne-burning in massive stars ({$>$}8 M{$\Sun$} initial mass) during + their post-main-sequence development are the only processes capable + of producing sufficiently large 29,30Si enrichments. This material + with heavy Si isotopic enrichments from the O/Ne and O/Si layers is + later incorporated into carbonaceous stardust, either in ejecta + from Type II supernovae or perhaps in the colliding winds of + Wolf--Rayet binaries. Although often too small for Si isotopic + measurements, four other SiC-containing graphites show other + signatures of a massive star origin. Abundance estimates suggest + that such unusual SiCs are present within {$\sim$}1\% of + high-density graphites. This abundance can be reconciled with the + much lower abundance in the overall SiC population if these unusual + SiCs are naturally smaller ({$\sim$}200 nm or less) than SiCs from + other isotopic subgroups and if differential destruction of small + unusual SiCs occurs in massive star outflows unless these SiCs are + encapsulated in graphite.}, + langid = {english}, } @article{SiC-2010-GYN-0, title = {Presolar {{SiC Grains}} of {{Type C}}}, author = {Gyngard, F. and Nittler, L. R. and Zinner, E.}, - year = {2010}, + year = 2010, month = sep, journal = {Meteoritics and Planetary Science Supplement}, volume = {73}, pages = {5242}, urldate = {2023-02-15}, - langid = {english} + langid = {english}, } @article{SiC-2010-HOP-0, - title = {{{NanoSIMS}} Studies of Small Presolar {{SiC}} Grains: {{New}} Insights into Supernova Nucleosynthesis, Chemistry, and Dust Formation}, + title = {{{NanoSIMS}} Studies of Small Presolar {{SiC}} Grains: {{New}} + Insights into Supernova Nucleosynthesis, Chemistry, and Dust Formation + }, shorttitle = {{{NanoSIMS STUDIES OF SMALL PRESOLAR SiC GRAINS}}}, - author = {Hoppe, Peter and Leitner, Jan and Gr{\"o}ner, Elmar and Marhas, Kuljeet K. and Meyer, Bradley S. and Amari, Sachiko}, - year = {2010}, + author = {Hoppe, Peter and Leitner, Jan and Gr{\"o}ner, Elmar and Marhas, + Kuljeet K. and Meyer, Bradley S. and Amari, Sachiko}, + year = 2010, month = jul, journal = {The Astrophysical Journal}, volume = {719}, @@ -1280,14 +2725,48 @@ @article{SiC-2010-HOP-0 issn = {0004-637X}, doi = {10.1088/0004-637X/719/2/1370}, urldate = {2023-02-15}, - abstract = {We have studied more than 2000 presolar silicon carbide (SiC) grains from the Murchison CM2 chondrite in the size range 0.2--0.5 {$\mu$}m for C- and Si-isotopic compositions. In a subset of these grains, we also measured N-, Mg--Al-, S-, and Ca--Ti-isotopic compositions as well as trace element concentrations. The overall picture emerging from the isotope data is quite comparable with that of larger grains, except for the abundances of grains from Type II supernovae (SNeII) and low-metallicity asymptotic giant branch (AGB) stars. Especially, the latter are much more abundant among submicrometer-sized grains than among micrometer-sized grains. This implies that SiC grains from lower-than-solar-metallicity AGB stars are on average smaller than those from solar metallicity AGB stars which provided the majority of presolar SiC grains. We identified five grains with large enrichments in 29Si (up to 3.5{\texttimes} solar) and 30Si (up to 3.9{\texttimes} solar in three of these grains). These grains are most likely from SNeII. The isotopically light S (32S/34S of 2{\texttimes} solar) together with the heavy Si in one of these grains suggests that molecule formation precedes macroscopic mixing and dust formation in SNII ejecta. This adds to the complexity of SN mixing calculations and should be considered in future studies. In total, about 2\% of the presolar SiC grains in the size range 0.2--0.5 {$\mu$}m appear to come from SNeII. This is about a factor of 2 higher than for micrometer-sized grains and suggests that SNeII, on average, produce smaller SiC grains than solar metallicity AGB stars. The high 29Si/30Si ratio in one of the SN grains suggests that current SN models underestimate the 29Si production in the C- and Ne-burning regions by about a factor of 2. It is shown that with this adjustment the solar 29Si/28Si ratio can be well reproduced in Galactic chemical evolution models and that a merger of our Galaxy with a low-metallicity satellite some 1.5 Gyr before solar system formation could account for the slope 1.3 of the Si mainstream line.}, - langid = {english} + abstract = {We have studied more than 2000 presolar silicon carbide (SiC) + grains from the Murchison CM2 chondrite in the size range 0.2--0.5 + {$\mu$}m for C- and Si-isotopic compositions. In a subset of these + grains, we also measured N-, Mg--Al-, S-, and Ca--Ti-isotopic + compositions as well as trace element concentrations. The overall + picture emerging from the isotope data is quite comparable with + that of larger grains, except for the abundances of grains from + Type II supernovae (SNeII) and low-metallicity asymptotic giant + branch (AGB) stars. Especially, the latter are much more abundant + among submicrometer-sized grains than among micrometer-sized + grains. This implies that SiC grains from + lower-than-solar-metallicity AGB stars are on average smaller than + those from solar metallicity AGB stars which provided the majority + of presolar SiC grains. We identified five grains with large + enrichments in 29Si (up to 3.5\texttimes{} solar) and 30Si (up to + 3.9\texttimes{} solar in three of these grains). These grains are + most likely from SNeII. The isotopically light S (32S/34S of 2 + \texttimes{} solar) together with the heavy Si in one of these + grains suggests that molecule formation precedes macroscopic mixing + and dust formation in SNII ejecta. This adds to the complexity of + SN mixing calculations and should be considered in future studies. + In total, about 2\% of the presolar SiC grains in the size range + 0.2--0.5 {$\mu$}m appear to come from SNeII. This is about a factor + of 2 higher than for micrometer-sized grains and suggests that + SNeII, on average, produce smaller SiC grains than solar + metallicity AGB stars. The high 29Si/30Si ratio in one of the SN + grains suggests that current SN models underestimate the 29Si + production in the C- and Ne-burning regions by about a factor of 2. + It is shown that with this adjustment the solar 29Si/28Si ratio can + be well reproduced in Galactic chemical evolution models and that a + merger of our Galaxy with a low-metallicity satellite some 1.5 Gyr + before solar system formation could account for the slope 1.3 of + the Si mainstream line.}, + langid = {english}, } @article{SiC-2010-NGU-0, - title = {Coordinated Analyses of Presolar Grains in the {{Allan Hills}} 77307 and {{Queen Elizabeth Range}} 99177 Meteorites}, - author = {Nguyen, Ann N. and Nittler, Larry R. and Stadermann, Frank J. and Stroud, Rhonda M. and Alexander, C. M. O'D.}, - year = {2010}, + title = {Coordinated Analyses of Presolar Grains in the {{Allan Hills}} 77307 + and {{Queen Elizabeth Range}} 99177 Meteorites}, + author = {Nguyen, Ann N. and Nittler, Larry R. and Stadermann, Frank J. and + Stroud, Rhonda M. and Alexander, C. M. O'D.}, + year = 2010, month = jul, journal = {The Astrophysical Journal}, volume = {719}, @@ -1297,14 +2776,44 @@ @article{SiC-2010-NGU-0 issn = {0004-637X}, doi = {10.1088/0004-637X/719/1/166}, urldate = {2023-02-15}, - abstract = {We report the identification of presolar silicates ({$\sim$}177 ppm), presolar oxides ({$\sim$}11 ppm), and one presolar SiO2 grain in the Allan Hills (ALHA) 77307 chondrite. Three grains having Si-isotopic compositions similar to SiC X and Z grains were also identified, though the mineral phases are unconfirmed. Similar abundances of presolar silicates ({$\sim$}152 ppm) and oxides ({$\sim$}8 ppm) were also uncovered in the primitive CR chondrite Queen Elizabeth Range (QUE) 99177, along with 13 presolar SiC grains and one presolar silicon nitride. The O-isotopic compositions of the presolar silicates and oxides indicate that most of the grains condensed in low-mass red giant and asymptotic giant branch stars. Interestingly, unlike presolar oxides, few presolar silicate grains have isotopic compositions pointing to low-metallicity, low-mass stars (Group 3). The 18O-rich (Group 4) silicates, along with the few Group 3 silicates that were identified, likely have origins in supernova outflows. This is supported by their O- and Si-isotopic compositions. Elemental compositions for 74 presolar silicate grains were determined by scanning Auger spectroscopy. Most of the grains have non-stoichiometric elemental compositions inconsistent with pyroxene or olivine, the phases commonly used to fit astronomical spectra, and have comparable Mg and Fe contents. Non-equilibrium condensation and/or secondary alteration could produce the high Fe contents. Transmission electron microscopic analysis of three silicate grains also reveals non-stoichiometric compositions, attributable to non-equilibrium or multistep condensation, and very fine scale elemental heterogeneity, possibly due to subsequent annealing. The mineralogies of presolar silicates identified in meteorites thus far seem to differ from those in interplanetary dust particles.}, - langid = {english} + abstract = {We report the identification of presolar silicates ({$\sim$}177 + ppm), presolar oxides ({$\sim$}11 ppm), and one presolar SiO2 grain + in the Allan Hills (ALHA) 77307 chondrite. Three grains having + Si-isotopic compositions similar to SiC X and Z grains were also + identified, though the mineral phases are unconfirmed. Similar + abundances of presolar silicates ({$\sim$}152 ppm) and oxides ({$ + \sim$}8 ppm) were also uncovered in the primitive CR chondrite + Queen Elizabeth Range (QUE) 99177, along with 13 presolar SiC + grains and one presolar silicon nitride. The O-isotopic + compositions of the presolar silicates and oxides indicate that + most of the grains condensed in low-mass red giant and asymptotic + giant branch stars. Interestingly, unlike presolar oxides, few + presolar silicate grains have isotopic compositions pointing to + low-metallicity, low-mass stars (Group 3). The 18O-rich (Group 4) + silicates, along with the few Group 3 silicates that were + identified, likely have origins in supernova outflows. This is + supported by their O- and Si-isotopic compositions. Elemental + compositions for 74 presolar silicate grains were determined by + scanning Auger spectroscopy. Most of the grains have + non-stoichiometric elemental compositions inconsistent with + pyroxene or olivine, the phases commonly used to fit astronomical + spectra, and have comparable Mg and Fe contents. Non-equilibrium + condensation and/or secondary alteration could produce the high Fe + contents. Transmission electron microscopic analysis of three + silicate grains also reveals non-stoichiometric compositions, + attributable to non-equilibrium or multistep condensation, and very + fine scale elemental heterogeneity, possibly due to subsequent + annealing. The mineralogies of presolar silicates identified in + meteorites thus far seem to differ from those in interplanetary + dust particles.}, + langid = {english}, } @article{SiC-2011-FUJ-0, - title = {Hints for Neutrino-Process Boron in Presolar Silicon Carbide Grains from Supernovae}, + title = {Hints for Neutrino-Process Boron in Presolar Silicon Carbide Grains + from Supernovae}, author = {Fujiya, Wataru and Hoppe, Peter and Ott, Ulrich}, - year = {2011}, + year = 2011, month = feb, journal = {The Astrophysical Journal Letters}, volume = {730}, @@ -1314,15 +2823,38 @@ @article{SiC-2011-FUJ-0 issn = {2041-8205}, doi = {10.1088/2041-8205/730/1/L7}, urldate = {2023-02-15}, - abstract = {We have studied more than 1000 presolar silicon carbide (SiC) grains from the Murchison CM2 chondrite for C- and Si-isotopic compositions. Twelve SiC X grains, characterized by strong enrichments in 28Si and believed to originate from Type II Supernovae (SNeII), were also measured for Li- and B-isotopic compositions. None of these grains show resolvable isotope anomalies in Li or B. For the seven X grains without Li and B contributions from nearby or attached SiC grains of distinct origins we find on average 7Li/6Li = 11.83 {\textpm} 0.29 (solar system: 12.06) and 11B/10B = 4.68 {\textpm} 0.31 (solar system: 4.03). The average 7Li/6Li is compatible with the solar system ratio and the lithium in the X grains is likely largely dominated by contaminating Li of laboratory or meteoritic origin. Also, most of the boron in X grains appears to be contamination but the small 11B excess of {$\sim$}16\%, significant at the 2{$\sigma$} level, can be considered a hint for the presence of boron produced by the neutrino process in the parent SNeII. Despite this finding, a quantitative comparison of the B isotope and abundance data of X grains with model predictions reveals deficiencies in our current understanding of the details of B production in SNeII as well as on B chemistry and condensation in SNII ejecta.}, - langid = {english} + abstract = {We have studied more than 1000 presolar silicon carbide (SiC) + grains from the Murchison CM2 chondrite for C- and Si-isotopic + compositions. Twelve SiC X grains, characterized by strong + enrichments in 28Si and believed to originate from Type II + Supernovae (SNeII), were also measured for Li- and B-isotopic + compositions. None of these grains show resolvable isotope + anomalies in Li or B. For the seven X grains without Li and B + contributions from nearby or attached SiC grains of distinct + origins we find on average 7Li/6Li = 11.83 \textpm{} 0.29 (solar + system: 12.06) and 11B/10B = 4.68 \textpm{} 0.31 (solar system: + 4.03). The average 7Li/6Li is compatible with the solar system + ratio and the lithium in the X grains is likely largely dominated + by contaminating Li of laboratory or meteoritic origin. Also, most + of the boron in X grains appears to be contamination but the small + 11B excess of {$\sim$}16\%, significant at the 2{$\sigma$} level, + can be considered a hint for the presence of boron produced by the + neutrino process in the parent SNeII. Despite this finding, a + quantitative comparison of the B isotope and abundance data of X + grains with model predictions reveals deficiencies in our current + understanding of the details of B production in SNeII as well as on + B chemistry and condensation in SNII ejecta.}, + langid = {english}, } @article{SiC-2012-BOS-0, - title = {Circumstellar and Interstellar Material in the {{CO3}} Chondrite {{ALHA77307}}: {{An}} Isotopic and Elemental Investigation}, - shorttitle = {Circumstellar and Interstellar Material in the {{CO3}} Chondrite {{ALHA77307}}}, - author = {Bose, Maitrayee and Floss, Christine and Stadermann, Frank J. and Stroud, Rhonda M. and Speck, Angela K.}, - year = {2012}, + title = {Circumstellar and Interstellar Material in the {{CO3}} Chondrite {{ + ALHA77307}}: {{An}} Isotopic and Elemental Investigation}, + shorttitle = {Circumstellar and Interstellar Material in the {{CO3}} Chondrite + {{ALHA77307}}}, + author = {Bose, Maitrayee and Floss, Christine and Stadermann, Frank J. and + Stroud, Rhonda M. and Speck, Angela K.}, + year = 2012, month = sep, journal = {Geochimica et Cosmochimica Acta}, volume = {93}, @@ -1330,15 +2862,55 @@ @article{SiC-2012-BOS-0 issn = {0016-7037}, doi = {10.1016/j.gca.2012.06.027}, urldate = {2023-02-15}, - abstract = {We have carried out a NanoSIMS C, N and O ion imaging study of the CO3.0 chondrite ALHA77307. The distribution of O-anomalous grains in ALHA77307 is similar to that observed in other primitive meteorites, and is dominated (84\%) by 17O-rich Group 1 grains from low-mass asymptotic giant branch (AGB) stars of close-to-solar metallicity. Four percent of the grains belong to Group 2, whose 18O depletions suggest cool-bottom processing in low-mass stars during the AGB phase, while 8\% are Group 4 grains with likely origins in Type II supernova (SN) ejecta. One ferromagnesian silicate has a very high 17O enrichment; nova explosions have been suggested as sources for such grains, but recent models with updated reaction rates show large discrepancies with the grain data, leaving the origins of these grains uncertain. Most of the grains are silicates (86\%) with the remainder consisting of oxides (8\%), three silica grains and two `composite' grains composed of multiple subgrains with different elemental compositions. The elemental compositions of the silicates are similar to those found in other studies, with a predominance of non-stoichiometric compositions and high (up to 44at.\%) Fe concentrations. A comparison of isotopic and elemental compositions for all presolar silicates shows that olivine compositions are overabundant in Group 4 grains compared to grains from Groups 1 and 2. This may reflect injection of presolar material from a nearby supernova into the early solar nebula and incorporation into parent bodies before alteration of compositions through irradiation and sputtering in the interstellar medium, as is likely to have occurred for the Group 1 and 2 grains from more distant AGB stars. The matrix material in ALHA77307 contains abundant carbonaceous hotspots with excesses in 15N. However, unlike CR chondrites, the insoluble organic matter (IOM) in ALHA77307 does not have a bulk N isotopic anomaly, consistent with Raman evidence that it has experienced more processing than IOM from CR chondrites. Nevertheless, secondary processing has clearly not been so pervasive as to lead to complete destruction of N isotopic anomalies in this meteorite. Moreover, presolar silicate abundances and elemental compositions show little evidence for thermal processing, indicating a decoupling of the effects of metamorphism on organic matter and matrix silicates.}, - langid = {english} + abstract = {We have carried out a NanoSIMS C, N and O ion imaging study of the + CO3.0 chondrite ALHA77307. The distribution of O-anomalous grains + in ALHA77307 is similar to that observed in other primitive + meteorites, and is dominated (84\%) by 17O-rich Group 1 grains from + low-mass asymptotic giant branch (AGB) stars of close-to-solar + metallicity. Four percent of the grains belong to Group 2, whose + 18O depletions suggest cool-bottom processing in low-mass stars + during the AGB phase, while 8\% are Group 4 grains with likely + origins in Type II supernova (SN) ejecta. One ferromagnesian + silicate has a very high 17O enrichment; nova explosions have been + suggested as sources for such grains, but recent models with + updated reaction rates show large discrepancies with the grain data + , leaving the origins of these grains uncertain. Most of the grains + are silicates (86\%) with the remainder consisting of oxides (8\%), + three silica grains and two `composite' grains composed of multiple + subgrains with different elemental compositions. The elemental + compositions of the silicates are similar to those found in other + studies, with a predominance of non-stoichiometric compositions and + high (up to 44at.\%) Fe concentrations. A comparison of isotopic + and elemental compositions for all presolar silicates shows that + olivine compositions are overabundant in Group 4 grains compared to + grains from Groups 1 and 2. This may reflect injection of presolar + material from a nearby supernova into the early solar nebula and + incorporation into parent bodies before alteration of compositions + through irradiation and sputtering in the interstellar medium, as + is likely to have occurred for the Group 1 and 2 grains from more + distant AGB stars. The matrix material in ALHA77307 contains + abundant carbonaceous hotspots with excesses in 15N. However, + unlike CR chondrites, the insoluble organic matter (IOM) in + ALHA77307 does not have a bulk N isotopic anomaly, consistent with + Raman evidence that it has experienced more processing than IOM + from CR chondrites. Nevertheless, secondary processing has clearly + not been so pervasive as to lead to complete destruction of N + isotopic anomalies in this meteorite. Moreover, presolar silicate + abundances and elemental compositions show little evidence for + thermal processing, indicating a decoupling of the effects of + metamorphism on organic matter and matrix silicates.}, + langid = {english}, } @article{SiC-2012-FLO-0, - title = {Presolar Silicate and Oxide Abundances and Compositions in the Ungrouped Carbonaceous Chondrite {{Adelaide}} and the {{K}} Chondrite {{Kakangari}}: {{The}} Effects of Secondary Processing}, - shorttitle = {Presolar Silicate and Oxide Abundances and Compositions in the Ungrouped Carbonaceous Chondrite {{Adelaide}} and the {{K}} Chondrite {{Kakangari}}}, + title = {Presolar Silicate and Oxide Abundances and Compositions in the + Ungrouped Carbonaceous Chondrite {{Adelaide}} and the {{K}} Chondrite + {{Kakangari}}: {{The}} Effects of Secondary Processing}, + shorttitle = {Presolar Silicate and Oxide Abundances and Compositions in the + Ungrouped Carbonaceous Chondrite {{Adelaide}} and the {{K}} + Chondrite {{Kakangari}}}, author = {Floss, Christine and Stadermann, Frank J.}, - year = {2012}, + year = 2012, journal = {Meteoritics \& Planetary Science}, volume = {47}, number = {6}, @@ -1346,14 +2918,32 @@ @article{SiC-2012-FLO-0 issn = {1945-5100}, doi = {10.1111/j.1945-5100.2012.01366.x}, urldate = {2023-02-15}, - abstract = {Abstract-- Although it has been suggested that the ungrouped carbonaceous chondrite Adelaide and the K chondrite Kakangari could be considered highly primitive, our study of their presolar grain abundances shows that both have experienced more secondary processing than other primitive chondrites with high presolar grain abundances. Presolar grains are rare in Kakangari and are present in reduced abundances in Adelaide (approximately 70 ppm for O-anomalous grains). Thermal annealing has led to widespread crystallization of their fine-grained matrices, and accounts for the partial to complete destruction of presolar grains. In addition, presolar silicates in Adelaide show elevated Fe abundances and Fe-rich rims indicative of infiltration of Fe into the grains from the surrounding matrix. This process probably also took place during annealing, most likely in the solar nebula, in a region with an enhanced dust-to-gas ratio. The most primitive meteorites, with the highest presolar grain abundances, appear to be those whose matrices contain abundant amorphous material that has escaped any significant thermal or aqueous alteration.}, - langid = {english} + abstract = {Abstract-- Although it has been suggested that the ungrouped + carbonaceous chondrite Adelaide and the K chondrite Kakangari could + be considered highly primitive, our study of their presolar grain + abundances shows that both have experienced more secondary + processing than other primitive chondrites with high presolar grain + abundances. Presolar grains are rare in Kakangari and are present + in reduced abundances in Adelaide (approximately 70 ppm for + O-anomalous grains). Thermal annealing has led to widespread + crystallization of their fine-grained matrices, and accounts for + the partial to complete destruction of presolar grains. In addition + , presolar silicates in Adelaide show elevated Fe abundances and + Fe-rich rims indicative of infiltration of Fe into the grains from + the surrounding matrix. This process probably also took place + during annealing, most likely in the solar nebula, in a region with + an enhanced dust-to-gas ratio. The most primitive meteorites, with + the highest presolar grain abundances, appear to be those whose + matrices contain abundant amorphous material that has escaped any + significant thermal or aqueous alteration.}, + langid = {english}, } @article{SiC-2012-HOP-0, - title = {Sulfur Molecule Chemistry in Supernova Ejecta Recorded by Silicon Carbide Stardust}, + title = {Sulfur Molecule Chemistry in Supernova Ejecta Recorded by Silicon + Carbide Stardust}, author = {Hoppe, Peter and Fujiya, Wataru and Zinner, Ernst}, - year = {2012}, + year = 2012, month = jan, journal = {The Astrophysical Journal Letters}, volume = {745}, @@ -1363,14 +2953,34 @@ @article{SiC-2012-HOP-0 issn = {2041-8205}, doi = {10.1088/2041-8205/745/2/L26}, urldate = {2023-02-15}, - abstract = {We studied about 3400 presolar silicon carbide (SiC) grains from the Murchison CM2 meteorite for C- and Si-isotopic compositions. Among these grains we identified 7 unusual or type C SiC (U/C) grains, characterized by isotopically heavy Si, and 36 supernova type X SiC grains, characterized by isotopically light Si. Selected U/C and X grains were also measured for S-, Mg--Al-, and Ca--Ti-isotopic compositions. We show that the U/C grains incorporated radioactive 44Ti, which is evidence that they formed in the ejecta of Type II supernova (SNII) explosions. Abundances of radioactive 26Al and 44Ti are compatible with those observed in X grains. U/C and X grains carry light S with enrichments in 32S of up to a factor of 2.7. The combination of heavy Si and light S observed in U/C grains is not consistent with abundance predictions of simple supernova models. The isotope data suggest preferential trapping of S from the innermost supernova zones, the production site of radioactive 44Ti, by the growing silicon carbide particles. A way to achieve this is by sulfur molecule chemistry in the still unmixed ejecta. This confirms model predictions of molecule formation in SNII ejecta and shows that sulfur molecule chemistry operates in the harsh and hot environments of stellar explosions.}, - langid = {english} + abstract = {We studied about 3400 presolar silicon carbide (SiC) grains from + the Murchison CM2 meteorite for C- and Si-isotopic compositions. + Among these grains we identified 7 unusual or type C SiC (U/C) + grains, characterized by isotopically heavy Si, and 36 supernova + type X SiC grains, characterized by isotopically light Si. Selected + U/C and X grains were also measured for S-, Mg--Al-, and + Ca--Ti-isotopic compositions. We show that the U/C grains + incorporated radioactive 44Ti, which is evidence that they formed + in the ejecta of Type II supernova (SNII) explosions. Abundances of + radioactive 26Al and 44Ti are compatible with those observed in X + grains. U/C and X grains carry light S with enrichments in 32S of + up to a factor of 2.7. The combination of heavy Si and light S + observed in U/C grains is not consistent with abundance predictions + of simple supernova models. The isotope data suggest preferential + trapping of S from the innermost supernova zones, the production + site of radioactive 44Ti, by the growing silicon carbide particles. + A way to achieve this is by sulfur molecule chemistry in the still + unmixed ejecta. This confirms model predictions of molecule + formation in SNII ejecta and shows that sulfur molecule chemistry + operates in the harsh and hot environments of stellar explosions.}, + langid = {english}, } @article{SiC-2012-LEI-0, - title = {Characterization of Presolar Material in the {{CR}} Chondrite {{Northwest Africa}} 852}, + title = {Characterization of Presolar Material in the {{CR}} Chondrite {{ + Northwest Africa}} 852}, author = {Leitner, J. and Vollmer, C. and Hoppe, P. and Zipfel, J.}, - year = {2011}, + year = 2011, month = dec, journal = {The Astrophysical Journal}, volume = {745}, @@ -1380,27 +2990,62 @@ @article{SiC-2012-LEI-0 issn = {0004-637X}, doi = {10.1088/0004-637X/745/1/38}, urldate = {2023-02-15}, - abstract = {We investigated the inventory of presolar silicate, oxide, and silicon carbide (SiC) grains in the CR2 chondrite Northwest Africa (NWA) 852. Thirty-one O-anomalous grains were detected: 24 were identified as silicates ({$\sim$}78 ppm); the remaining 7 are Al-rich oxides ({$\sim$}38 ppm). NWA 852 is the first C2 chondrite containing O-anomalous presolar dust in concentrations comparable to other more primitive meteorites. Eight presolar SiC grains have been found, representing the highest abundance ({$\sim$}160 ppm) observed so far in primitive meteorites. 15N-enriched matter is also present, although very heterogeneously distributed. Twenty-six of the O-anomalous grains are enriched in 17O, originating from the outflows of low-mass asymptotic giant branch (AGB) stars. We calculate a silicate/oxide abundance ratio of {$\sim$}2, which indicates a higher degree of aqueous alteration than observed for other presolar-grain-rich meteorites. NWA 852 thus stands between the presolar-grain-rich CR3 chondrites (MET 00426, QUE 99177) and CR2 chondrites with low presolar grain abundances (Renazzo, NWA 530). We calculate an initial presolar silicate abundance of {$\sim$}800 ppm for NWA 852, if silicate destruction by aqueous alteration is taken into account. Transmission electron microscope (TEM) investigation of one presolar Al-rich grain of an AGB star origin revealed that the grain mainly consists of a single crystal of hibonite with slightly varying orientations. A distinct subgrain (d {$<$} 100 nm) with a Ca/Ti ratio of {$\sim$}1 is located in the central region, most likely indicating a perovskite-like phase. Our data suggest this phase to be a primary condensate and not an alteration product.}, - langid = {english} + abstract = {We investigated the inventory of presolar silicate, oxide, and + silicon carbide (SiC) grains in the CR2 chondrite Northwest Africa + (NWA) 852. Thirty-one O-anomalous grains were detected: 24 were + identified as silicates ({$\sim$}78 ppm); the remaining 7 are + Al-rich oxides ({$\sim$}38 ppm). NWA 852 is the first C2 chondrite + containing O-anomalous presolar dust in concentrations comparable + to other more primitive meteorites. Eight presolar SiC grains have + been found, representing the highest abundance ({$\sim$}160 ppm) + observed so far in primitive meteorites. 15N-enriched matter is + also present, although very heterogeneously distributed. Twenty-six + of the O-anomalous grains are enriched in 17O, originating from the + outflows of low-mass asymptotic giant branch (AGB) stars. We + calculate a silicate/oxide abundance ratio of {$\sim$}2, which + indicates a higher degree of aqueous alteration than observed for + other presolar-grain-rich meteorites. NWA 852 thus stands between + the presolar-grain-rich CR3 chondrites (MET 00426, QUE 99177) and + CR2 chondrites with low presolar grain abundances (Renazzo, NWA + 530). We calculate an initial presolar silicate abundance of {$\sim + $}800 ppm for NWA 852, if silicate destruction by aqueous + alteration is taken into account. Transmission electron microscope + (TEM) investigation of one presolar Al-rich grain of an AGB star + origin revealed that the grain mainly consists of a single crystal + of hibonite with slightly varying orientations. A distinct subgrain + (d {$<$} 100 nm) with a Ca/Ti ratio of {$\sim$}1 is located in the + central region, most likely indicating a perovskite-like phase. Our + data suggest this phase to be a primary condensate and not an + alteration product.}, + langid = {english}, } @inproceedings{SiC-2012-ORT-0, - title = {Multi-Element Isotopic Compositions of Presolar {{SiC}} Grains from the {{Indarch}} Meteorite}, + title = {Multi-Element Isotopic Compositions of Presolar {{SiC}} Grains from + the {{Indarch}} Meteorite}, booktitle = {Lunar and {{Planetary Science Conference}}}, - author = {{Orthous-Daunay}, F. -R. and Gyngard, F. and Moynier, F. and Zinner, E.}, - year = {2012}, + author = {{Orthous-Daunay}, F. -R. and Gyngard, F. and Moynier, F. and Zinner, + E.}, + year = 2012, volume = {43}, pages = {2679}, urldate = {2023-02-15}, - abstract = {We present a NanoSIMS study of grains isolated from Indarch with sizes between 0.4 and 1 {\textmu}m. Si and C isotopic compositions of more than thousand particles were measured. Grains with extreme anomalies were selected for multi-element investigation.}, - annotation = {ADS Bibcode: 2012LPI....43.2679O} + abstract = {We present a NanoSIMS study of grains isolated from Indarch with + sizes between 0.4 and 1 \textmu m. Si and C isotopic compositions + of more than thousand particles were measured. Grains with extreme + anomalies were selected for multi-element investigation.}, } @article{SiC-2013-AVI-0, - title = {Ba Isotopic Compositions in Stardust {{SiC}} Grains from the {{Murchison}} Meteorite: {{Insights}} into the Stellar Origins of Large {{SiC}} Grains}, - shorttitle = {Ba Isotopic Compositions in Stardust {{SiC}} Grains from the {{Murchison}} Meteorite}, - author = {{\'A}vila, Jana{\'i}na N. and Ireland, Trevor R. and Gyngard, Frank and Zinner, Ernst and Mallmann, Guilherme and Lugaro, Maria and Holden, Peter and Amari, Sachiko}, - year = {2013}, + title = {Ba Isotopic Compositions in Stardust {{SiC}} Grains from the {{ + Murchison}} Meteorite: {{Insights}} into the Stellar Origins of Large + {{SiC}} Grains}, + shorttitle = {Ba Isotopic Compositions in Stardust {{SiC}} Grains from the {{ + Murchison}} Meteorite}, + author = {{\'A}vila, Jana{\'i}na N. and Ireland, Trevor R. and Gyngard, Frank + and Zinner, Ernst and Mallmann, Guilherme and Lugaro, Maria and + Holden, Peter and Amari, Sachiko}, + year = 2013, month = nov, journal = {Geochimica et Cosmochimica Acta}, volume = {120}, @@ -1408,14 +3053,45 @@ @article{SiC-2013-AVI-0 issn = {0016-7037}, doi = {10.1016/j.gca.2013.03.039}, urldate = {2023-02-15}, - abstract = {We report barium isotopic measurements in 12 large (7--58{$\mu$}m) stardust silicon carbide grains recovered from the Murchison carbonaceous chondrite. The C-, N-, and Si-isotopic compositions indicate that all 12 grains belong to the mainstream population and, as such, are interpreted to have condensed in the outflows of low-mass carbon-rich asymptotic giant branch (AGB) stars with close-to-solar metallicity. Barium isotopic analyses were carried out on the Sensitive High Resolution Ion Microprobe -- Reverse Geometry (SHRIMP-RG) with combined high mass resolution and energy filtering to eliminate isobaric interferences from molecular ions. Contrary to previous measurements in small ({$<$}5{$\mu$}m) mainstream grains, the analyzed large SiC grains do not show the classical s-process enrichment, having near solar Ba isotopic compositions. While contamination with solar material is a common explanation for the lack of large isotopic anomalies in stardust SiC grains, particularly for these large grains which have low trace element abundances, our results are consistent with previous observations that Ba isotopic ratios are dependent on grain size. We have compared the SiC data with theoretical predictions of the evolution of Ba isotopic ratios in the envelopes of low-mass AGB stars with a range of stellar masses and metallicities. The Ba isotopic measurements obtained for large SiC grains from the LS+LU fractions are consistent with grain condensation in the envelope of very low-mass AGB stars (1.25M{$\odot$}) with close-to-solar metallicity, which suggests that conditions for growth of large SiC might be more favorable in very low-mass AGB stars during the early C-rich stages of AGB evolution or in stable structures around AGB stars whose evolution was cut short due to binary interaction, before the AGB envelope had already been largely enriched with the products of s-process nucleosynthesis.}, - langid = {english} + abstract = {We report barium isotopic measurements in 12 large (7--58{$\mu$}m) + stardust silicon carbide grains recovered from the Murchison + carbonaceous chondrite. The C-, N-, and Si-isotopic compositions + indicate that all 12 grains belong to the mainstream population and + , as such, are interpreted to have condensed in the outflows of + low-mass carbon-rich asymptotic giant branch (AGB) stars with + close-to-solar metallicity. Barium isotopic analyses were carried + out on the Sensitive High Resolution Ion Microprobe -- Reverse + Geometry (SHRIMP-RG) with combined high mass resolution and energy + filtering to eliminate isobaric interferences from molecular ions. + Contrary to previous measurements in small ({$<$}5{$\mu$}m) + mainstream grains, the analyzed large SiC grains do not show the + classical s-process enrichment, having near solar Ba isotopic + compositions. While contamination with solar material is a common + explanation for the lack of large isotopic anomalies in stardust + SiC grains, particularly for these large grains which have low + trace element abundances, our results are consistent with previous + observations that Ba isotopic ratios are dependent on grain size. + We have compared the SiC data with theoretical predictions of the + evolution of Ba isotopic ratios in the envelopes of low-mass AGB + stars with a range of stellar masses and metallicities. The Ba + isotopic measurements obtained for large SiC grains from the LS+LU + fractions are consistent with grain condensation in the envelope of + very low-mass AGB stars (1.25M{$\odot$}) with close-to-solar + metallicity, which suggests that conditions for growth of large SiC + might be more favorable in very low-mass AGB stars during the early + C-rich stages of AGB evolution or in stable structures around AGB + stars whose evolution was cut short due to binary interaction, + before the AGB envelope had already been largely enriched with the + products of s-process nucleosynthesis.}, + langid = {english}, } @article{SiC-2013-FUJ-0, - title = {Evidence for Radiogenic Sulfur-32 in Type {{AB}} Presolar Silicon Carbide Grains?}, - author = {Fujiya, Wataru and Hoppe, Peter and Zinner, Ernst and Pignatari, Marco and Herwig, Falk}, - year = {2013}, + title = {Evidence for Radiogenic Sulfur-32 in Type {{AB}} Presolar Silicon + Carbide Grains?}, + author = {Fujiya, Wataru and Hoppe, Peter and Zinner, Ernst and Pignatari, + Marco and Herwig, Falk}, + year = 2013, month = oct, journal = {The Astrophysical Journal Letters}, volume = {776}, @@ -1425,14 +3101,37 @@ @article{SiC-2013-FUJ-0 issn = {2041-8205}, doi = {10.1088/2041-8205/776/2/L29}, urldate = {2023-02-15}, - abstract = {We report C, Si, and S isotope measurements on 34 presolar silicon carbide grains of Type AB, characterized by 12C/13C {$<$} 10. Nitrogen, Mg--Al-, and Ca--Ti-isotopic compositions were measured on a subset of these grains. Three grains show large 32S excesses, a signature that has been previously observed for grains from supernovae (SNe). Enrichments in 32S may be due to contributions from the Si/S zone and the result of S molecule chemistry in still unmixed SN ejecta or due to incorporation of radioactive 32Si from C-rich explosive He shell ejecta. However, a SN origin remains unlikely for the three AB grains considered here, because of missing evidence for 44Ti, relatively low 26Al/27Al ratios (a few times 10-3), and radiogenic 32S along with low 12C/13C ratios. Instead, we show that born-again asymptotic giant branch (AGB) stars that have undergone a very-late thermal pulse (VLTP), known to have low 12C/13C ratios and enhanced abundances of the light s-process elements, can produce 32Si, which makes such stars attractive sources for AB grains with 32S excesses. This lends support to the proposal that at least some AB grains originate from born-again AGB stars, although uncertainties in the born-again AGB star models and possible variations of initial S-isotopic compositions in the parent stars of AB grains make it difficult to draw a definitive conclusion.}, - langid = {english} + abstract = {We report C, Si, and S isotope measurements on 34 presolar silicon + carbide grains of Type AB, characterized by 12C/13C {$<$} 10. + Nitrogen, Mg--Al-, and Ca--Ti-isotopic compositions were measured + on a subset of these grains. Three grains show large 32S excesses, + a signature that has been previously observed for grains from + supernovae (SNe). Enrichments in 32S may be due to contributions + from the Si/S zone and the result of S molecule chemistry in still + unmixed SN ejecta or due to incorporation of radioactive 32Si from + C-rich explosive He shell ejecta. However, a SN origin remains + unlikely for the three AB grains considered here, because of + missing evidence for 44Ti, relatively low 26Al/27Al ratios (a few + times 10-3), and radiogenic 32S along with low 12C/13C ratios. + Instead, we show that born-again asymptotic giant branch (AGB) + stars that have undergone a very-late thermal pulse (VLTP), known + to have low 12C/13C ratios and enhanced abundances of the light + s-process elements, can produce 32Si, which makes such stars + attractive sources for AB grains with 32S excesses. This lends + support to the proposal that at least some AB grains originate from + born-again AGB stars, although uncertainties in the born-again AGB + star models and possible variations of initial S-isotopic + compositions in the parent stars of AB grains make it difficult to + draw a definitive conclusion.}, + langid = {english}, } @article{SiC-2013-ZHA-0, - title = {Stardust Investigation into the {{CR}} Chondrite {{Grove Mountain}} 021710}, - author = {Zhao, Xuchao and Floss, Christine and Lin, Yangting and Bose, Maitrayee}, - year = {2013}, + title = {Stardust Investigation into the {{CR}} Chondrite {{Grove Mountain}} + 021710}, + author = {Zhao, Xuchao and Floss, Christine and Lin, Yangting and Bose, + Maitrayee}, + year = 2013, month = may, journal = {The Astrophysical Journal}, volume = {769}, @@ -1442,15 +3141,44 @@ @article{SiC-2013-ZHA-0 issn = {0004-637X}, doi = {10.1088/0004-637X/769/1/49}, urldate = {2023-02-15}, - abstract = {We report the presolar grain inventory of the CR chondrite Grove Mountain 021710. A total of 35 C-anomalous grains ({$\sim$}236 ppm) and 112 O-anomalous grains ({$\sim$}189 ppm) were identified in situ using NanoSIMS ion imaging. Of 35 C-anomalous grains, 28 were determined to be SiC grains by Auger spectroscopy. Seven of the SiC grains were subsequently measured for N and Si isotopes, allowing classification as one nova grain, one Y grain, one Z grain, and four mainstream grains. Eighty-nine out of 112 O-anomalous grains belong to Group 1, indicating origins in low-to-intermediate-mass red giant and asymptotic giant branch stars. Twenty-one are Group 4 grains and have origins in supernovae. Auger spectroscopic elemental measurements of 35 O-anomalous grains show that 33 of them are ferromagnesian silicates. They have higher Mg/(Mg+Fe) ratios than those reported in other meteorites, suggesting a lower degree of alteration in the nebula and/or asteroid parent bodies. Only two oxide grains were identified, with stoichiometric compositions of MgAl2O4 and SiO2, respectively. The presolar silicate/oxide ratio of GRV 021710 is comparable with those of the CR3 chondrites (QUE 99177 and MET 00426) and primitive interplanetary dust particles. In order to search for presolar sulfides, the meteorite was also mapped for S isotopes. However, no presolar sulfides were found, suggesting a maximum abundance of 2 ppm. The scarcity of presolar sulfides may be due to their much faster sputtering rate by cosmic rays compared to silicates.}, - langid = {english} + abstract = {We report the presolar grain inventory of the CR chondrite Grove + Mountain 021710. A total of 35 C-anomalous grains ({$\sim$}236 ppm) + and 112 O-anomalous grains ({$\sim$}189 ppm) were identified in + situ using NanoSIMS ion imaging. Of 35 C-anomalous grains, 28 were + determined to be SiC grains by Auger spectroscopy. Seven of the SiC + grains were subsequently measured for N and Si isotopes, allowing + classification as one nova grain, one Y grain, one Z grain, and + four mainstream grains. Eighty-nine out of 112 O-anomalous grains + belong to Group 1, indicating origins in low-to-intermediate-mass + red giant and asymptotic giant branch stars. Twenty-one are Group 4 + grains and have origins in supernovae. Auger spectroscopic + elemental measurements of 35 O-anomalous grains show that 33 of + them are ferromagnesian silicates. They have higher Mg/(Mg+Fe) + ratios than those reported in other meteorites, suggesting a lower + degree of alteration in the nebula and/or asteroid parent bodies. + Only two oxide grains were identified, with stoichiometric + compositions of MgAl2O4 and SiO2, respectively. The presolar + silicate/oxide ratio of GRV 021710 is comparable with those of the + CR3 chondrites (QUE 99177 and MET 00426) and primitive + interplanetary dust particles. In order to search for presolar + sulfides, the meteorite was also mapped for S isotopes. However, no + presolar sulfides were found, suggesting a maximum abundance of 2 + ppm. The scarcity of presolar sulfides may be due to their much + faster sputtering rate by cosmic rays compared to silicates.}, + langid = {english}, } @article{SiC-2014-LIU-0, - title = {Barium Isotopic Composition of Mainstream Silicon Carbides from {{Murchison}}: {{Constraints}} for {\emph{s}}-Process Nucleosynthesis in Asymptotic Giant Branch Stars}, - shorttitle = {{{BARIUM ISOTOPIC COMPOSITION OF MAINSTREAM SILICON CARBIDES FROM MURCHISON}}}, - author = {Liu, Nan and Savina, Michael R. and Davis, Andrew M. and Gallino, Roberto and Straniero, Oscar and Gyngard, Frank and Pellin, Michael J. and Willingham, David G. and Dauphas, Nicolas and Pignatari, Marco and Bisterzo, Sara and Cristallo, Sergio and Herwig, Falk}, - year = {2014}, + title = {Barium Isotopic Composition of Mainstream Silicon Carbides from {{ + Murchison}}: {{Constraints}} for {\emph{s}}-Process Nucleosynthesis in + Asymptotic Giant Branch Stars}, + shorttitle = {{{BARIUM ISOTOPIC COMPOSITION OF MAINSTREAM SILICON CARBIDES + FROM MURCHISON}}}, + author = {Liu, Nan and Savina, Michael R. and Davis, Andrew M. and Gallino, + Roberto and Straniero, Oscar and Gyngard, Frank and Pellin, Michael + J. and Willingham, David G. and Dauphas, Nicolas and Pignatari, Marco + and Bisterzo, Sara and Cristallo, Sergio and Herwig, Falk}, + year = 2014, month = apr, journal = {The Astrophysical Journal}, volume = {786}, @@ -1460,14 +3188,44 @@ @article{SiC-2014-LIU-0 issn = {0004-637X}, doi = {10.1088/0004-637X/786/1/66}, urldate = {2023-02-15}, - abstract = {We present barium, carbon, and silicon isotopic compositions of 38 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing barium contamination. Strong depletions in {$\delta$}(138Ba/136Ba) values are found, down to -400‰, which can only be modeled with a flatter 13C profile within the 13C pocket than is normally used. The dependence of {$\delta$}(138Ba/136Ba) predictions on the distribution of 13C within the pocket in asymptotic giant branch (AGB) models allows us to probe the 13C profile within the 13C pocket and the pocket mass in AGB stars. In addition, we provide constraints on the 22Ne({$\alpha$}, n)25Mg rate in the stellar temperature regime relevant to AGB stars, based on {$\delta$}(134Ba/136Ba) values of mainstream grains. We found two nominally mainstream grains with strongly negative {$\delta$}(134Ba/136Ba) values that cannot be explained by any of the current AGB model calculations. Instead, such negative values are consistent with the intermediate neutron capture process (i process), which is activated by the very late thermal pulse during the post-AGB phase and characterized by a neutron density much higher than the s process. These two grains may have condensed around post-AGB stars. Finally, we report abundances of two p-process isotopes, 130Ba and 132Ba, in single SiC grains. These isotopes are destroyed in the s process in AGB stars. By comparing their abundances with respect to that of 135Ba, we conclude that there is no measurable decay of 135Cs (t1/2 = 2.3 Ma) to 135Ba in individual SiC grains, indicating condensation of barium, but not cesium into SiC grains before 135Cs decayed.}, - langid = {english} + abstract = {We present barium, carbon, and silicon isotopic compositions of 38 + acid-cleaned presolar SiC grains from Murchison. Comparison with + previous data shows that acid washing is highly effective in + removing barium contamination. Strong depletions in {$\delta$} + (138Ba/136Ba) values are found, down to -400‰, which can only be + modeled with a flatter 13C profile within the 13C pocket than is + normally used. The dependence of {$\delta$}(138Ba/136Ba) + predictions on the distribution of 13C within the pocket in + asymptotic giant branch (AGB) models allows us to probe the 13C + profile within the 13C pocket and the pocket mass in AGB stars. In + addition, we provide constraints on the 22Ne({$\alpha$}, n)25Mg + rate in the stellar temperature regime relevant to AGB stars, based + on {$\delta$}(134Ba/136Ba) values of mainstream grains. We found + two nominally mainstream grains with strongly negative {$\delta$} + (134Ba/136Ba) values that cannot be explained by any of the current + AGB model calculations. Instead, such negative values are + consistent with the intermediate neutron capture process (i + process), which is activated by the very late thermal pulse during + the post-AGB phase and characterized by a neutron density much + higher than the s process. These two grains may have condensed + around post-AGB stars. Finally, we report abundances of two + p-process isotopes, 130Ba and 132Ba, in single SiC grains. These + isotopes are destroyed in the s process in AGB stars. By comparing + their abundances with respect to that of 135Ba, we conclude that + there is no measurable decay of 135Cs (t1/2 = 2.3 Ma) to 135Ba in + individual SiC grains, indicating condensation of barium, but not + cesium into SiC grains before 135Cs decayed.}, + langid = {english}, } @article{SiC-2015-LIU-0, - title = {Correlated Strontium and Barium Isotopic Compositions of Acid-Cleaned Single Mainstream Silicon Carbides from {{Murchison}}}, - author = {Liu, Nan and Savina, Michael R. and Gallino, Roberto and Davis, Andrew M. and Bisterzo, Sara and Gyngard, Frank and K{\"a}ppeler, Franz and Cristallo, Sergio and Dauphas, Nicolas and Pellin, Michael J. and Dillmann, Iris}, - year = {2015}, + title = {Correlated Strontium and Barium Isotopic Compositions of Acid-Cleaned + Single Mainstream Silicon Carbides from {{Murchison}}}, + author = {Liu, Nan and Savina, Michael R. and Gallino, Roberto and Davis, + Andrew M. and Bisterzo, Sara and Gyngard, Frank and K{\"a}ppeler, + Franz and Cristallo, Sergio and Dauphas, Nicolas and Pellin, Michael + J. and Dillmann, Iris}, + year = 2015, month = apr, journal = {The Astrophysical Journal}, volume = {803}, @@ -1477,14 +3235,28 @@ @article{SiC-2015-LIU-0 issn = {0004-637X}, doi = {10.1088/0004-637X/803/1/12}, urldate = {2023-02-15}, - abstract = {We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing both strontium and barium contamination. For the first time, by using correlated 88Sr/86Sr and 138Ba/136Ba ratios in mainstream SiC grains, we are able to resolve the effect of 13C concentration from that of 13C-pocket mass on s-process nucleosynthesis, which points toward the existence of large 13C pockets with low 13C concentrations in asymptotic giant branch stars. The presence of such large 13C pockets with a variety of relatively low 13C concentrations seems to require multiple mixing processes in parent asymptotic giant branch stars of mainstream SiC grains.}, - langid = {english} + abstract = {We present strontium, barium, carbon, and silicon isotopic + compositions of 61 acid-cleaned presolar SiC grains from Murchison. + Comparison with previous data shows that acid washing is highly + effective in removing both strontium and barium contamination. For + the first time, by using correlated 88Sr/86Sr and 138Ba/136Ba + ratios in mainstream SiC grains, we are able to resolve the effect + of 13C concentration from that of 13C-pocket mass on s-process + nucleosynthesis, which points toward the existence of large 13C + pockets with low 13C concentrations in asymptotic giant branch + stars. The presence of such large 13C pockets with a variety of + relatively low 13C concentrations seems to require multiple mixing + processes in parent asymptotic giant branch stars of mainstream SiC + grains.}, + langid = {english}, } @article{SiC-2015-XUY-0, - title = {Sulfur Isotopic Compositions of Submicrometer {{SiC}} Grains from the {{Murchison}} Meteorite}, - author = {Xu, Yuchen and Zinner, Ernst and Gallino, Roberto and Heger, Alexander and Pignatari, Marco and Lin, Yangting}, - year = {2015}, + title = {Sulfur Isotopic Compositions of Submicrometer {{SiC}} Grains from the + {{Murchison}} Meteorite}, + author = {Xu, Yuchen and Zinner, Ernst and Gallino, Roberto and Heger, + Alexander and Pignatari, Marco and Lin, Yangting}, + year = 2015, month = jan, journal = {The Astrophysical Journal}, volume = {799}, @@ -1494,15 +3266,43 @@ @article{SiC-2015-XUY-0 issn = {0004-637X}, doi = {10.1088/0004-637X/799/2/156}, urldate = {2023-02-15}, - abstract = {We report C, Si, N, S, Mg--Al, and Ca--Ti isotopic compositions of presolar silicon carbide (SiC) grains from the SiC-rich KJE size fraction (0.5--0.8 {$\mu$}m) of the Murchison meteorite. One thousand one hundred thirteen SiC grains were identified based on their C and Si isotopic ratios. Mainstream, AB, C, X, Y, and Z subtypes of SiC, and X-type silicon nitride (Si3N4) account for 81.4\%, 5.7\%, 0.1\%, 1.5\%, 5.8\%, 4.9\%, and 0.4\%, respectively. Twenty-five grains with unusual Si isotopic ratios, including one C grain, 16 X grains, 1 Y grain, 5 Z grains, and 2 X-type Si3N4 grains were selected for N, S, Mg--Al, and Ca--Ti isotopic analysis. The C grain is highly enriched in 29Si and 30Si ({$\delta$}29Si = 1345‰ {\textpm} 19‰, {$\delta$}30Si = 1272‰ {\textpm} 19‰). It has a huge 32S excess, larger than any seen before, and larger than that predicted for the Si/S supernova (SN) zone, providing evidence against the elemental fractionation model by Hoppe et al. Two SN models investigated here present a more satisfying explanation in terms of a radiogenic origin of 32S from the decay of short-lived 32Si ({$\tau$}1/2 = 153 yr). Silicon-32 as well as 29Si and 30Si can be produced in SNe by short neutron bursts; evidence for initial 44Ti ({$\tau$}1/2 = 60 yr) in the C grain is additional evidence for an SN origin. The X grains have marginal 32S excesses, much smaller than expected from their large 28Si excesses. Similarly, the Y and Z grains do not show the S-isotopic anomalies expected from their large Si isotopic anomalies. Low intrinsic S contents and contamination with isotopically normal S are the most likely explanations.}, - langid = {english} + abstract = {We report C, Si, N, S, Mg--Al, and Ca--Ti isotopic compositions of + presolar silicon carbide (SiC) grains from the SiC-rich KJE size + fraction (0.5--0.8 {$\mu$}m) of the Murchison meteorite. One + thousand one hundred thirteen SiC grains were identified based on + their C and Si isotopic ratios. Mainstream, AB, C, X, Y, and Z + subtypes of SiC, and X-type silicon nitride (Si3N4) account for + 81.4\%, 5.7\%, 0.1\%, 1.5\%, 5.8\%, 4.9\%, and 0.4\%, respectively. + Twenty-five grains with unusual Si isotopic ratios, including one C + grain, 16 X grains, 1 Y grain, 5 Z grains, and 2 X-type Si3N4 + grains were selected for N, S, Mg--Al, and Ca--Ti isotopic + analysis. The C grain is highly enriched in 29Si and 30Si ({$\delta + $}29Si = 1345‰ \textpm{} 19‰, {$\delta$}30Si = 1272‰ \textpm{} + 19‰). It has a huge 32S excess, larger than any seen before, and + larger than that predicted for the Si/S supernova (SN) zone, + providing evidence against the elemental fractionation model by + Hoppe et al. Two SN models investigated here present a more + satisfying explanation in terms of a radiogenic origin of 32S from + the decay of short-lived 32Si ({$\tau$}1/2 = 153 yr). Silicon-32 as + well as 29Si and 30Si can be produced in SNe by short neutron + bursts; evidence for initial 44Ti ({$\tau$}1/2 = 60 yr) in the C + grain is additional evidence for an SN origin. The X grains have + marginal 32S excesses, much smaller than expected from their large + 28Si excesses. Similarly, the Y and Z grains do not show the + S-isotopic anomalies expected from their large Si isotopic + anomalies. Low intrinsic S contents and contamination with + isotopically normal S are the most likely explanations.}, + langid = {english}, } @article{SiC-2016-LIU-0, - title = {Stellar Origins of Extremely {\textsuperscript{13}}{{C-}} and {\textsuperscript{15}}{{N-enriched}} Presolar {{siC}} Grains: {{Novae}} or Supernovae?}, - shorttitle = {{{S}}TEL{{LAR ORIGINS OF EXTREMELY 13C- AND 15N-ENRICHED PRESOLAR SIC GRAINS}}}, - author = {Liu, Nan and Nittler, Larry R. and Alexander, C. M. O'D. and Wang, Jianhua and Pignatari, Marco and Jos{\'e}, Jordi and Nguyen, Ann}, - year = {2016}, + title = {Stellar Origins of Extremely {$^{13}$}{{C-}} and {$^{15}$}{{ + N-enriched}} Presolar {{siC}} Grains: {{Novae}} or Supernovae?}, + shorttitle = {{{STELLAR ORIGINS OF EXTREMELY 13C- AND 15N-ENRICHED PRESOLAR + SIC GRAINS}}}, + author = {Liu, Nan and Nittler, Larry R. and Alexander, C. M. O'D. and Wang, + Jianhua and Pignatari, Marco and Jos{\'e}, Jordi and Nguyen, Ann}, + year = 2016, month = mar, journal = {The Astrophysical Journal}, volume = {820}, @@ -1512,15 +3312,45 @@ @article{SiC-2016-LIU-0 issn = {0004-637X}, doi = {10.3847/0004-637X/820/2/140}, urldate = {2023-02-15}, - abstract = {Extreme excesses of 13C (12C/13C {$<$} 10) and 15N (14N/15N {$<$} 20) in rare presolar SiC grains have been considered diagnostic of an origin in classical novae, though an origin in core collapse supernovae (CCSNe) has also been proposed. We report C, N, and Si isotope data for 14 submicron- to micron-sized 13C- and 15N-enriched presolar SiC grains (12C/13C {$<$} 16 and 14N/15N {$<$} {$\sim$}100) from Murchison, and their correlated Mg--Al, S, and Ca--Ti isotope data when available. These grains are enriched in 13C and 15N, but with quite diverse Si isotopic signatures. Four grains with 29,30Si excesses similar to those of type C SiC grains likely came from CCSNe, which experienced explosive H burning occurred during explosions. The independent coexistence of proton- and neutron-capture isotopic signatures in these grains strongly supports heterogeneous H ingestion into the He shell in pre-supernovae. Two of the seven putative nova grains with 30Si excesses and 29Si depletions show lower-than-solar 34S/32S ratios that cannot be explained by classical nova nucleosynthetic models. We discuss these signatures within the CCSN scenario. For the remaining five putative nova grains, both nova and supernova origins are viable because explosive H burning in the two stellar sites could result in quite similar proton-capture isotopic signatures. Three of the grains are sub-type AB grains that are also 13C enriched, but have a range of higher 14N/15N. We found that 15N-enriched AB grains ({$\sim$}50 {$<$} 14N/15N {$<$} {$\sim$}100) have distinctive isotopic signatures compared to putative nova grains, such as higher 14N/15N, lower 26Al/27Al, and lack of 30Si excess, indicating weaker proton-capture nucleosynthetic environments.}, - langid = {english} + abstract = {Extreme excesses of 13C (12C/13C {$<$} 10) and 15N (14N/15N {$<$} + 20) in rare presolar SiC grains have been considered diagnostic of + an origin in classical novae, though an origin in core collapse + supernovae (CCSNe) has also been proposed. We report C, N, and Si + isotope data for 14 submicron- to micron-sized 13C- and + 15N-enriched presolar SiC grains (12C/13C {$<$} 16 and 14N/15N {$<$ + } {$\sim$}100) from Murchison, and their correlated Mg--Al, S, and + Ca--Ti isotope data when available. These grains are enriched in + 13C and 15N, but with quite diverse Si isotopic signatures. Four + grains with 29,30Si excesses similar to those of type C SiC grains + likely came from CCSNe, which experienced explosive H burning + occurred during explosions. The independent coexistence of proton- + and neutron-capture isotopic signatures in these grains strongly + supports heterogeneous H ingestion into the He shell in + pre-supernovae. Two of the seven putative nova grains with 30Si + excesses and 29Si depletions show lower-than-solar 34S/32S ratios + that cannot be explained by classical nova nucleosynthetic models. + We discuss these signatures within the CCSN scenario. For the + remaining five putative nova grains, both nova and supernova + origins are viable because explosive H burning in the two stellar + sites could result in quite similar proton-capture isotopic + signatures. Three of the grains are sub-type AB grains that are + also 13C enriched, but have a range of higher 14N/15N. We found + that 15N-enriched AB grains ({$\sim$}50 {$<$} 14N/15N {$<$} {$\sim$ + } 100) have distinctive isotopic signatures compared to putative + nova grains, such as higher 14N/15N, lower 26Al/27Al, and lack of + 30Si excess, indicating weaker proton-capture nucleosynthetic + environments.}, + langid = {english}, } @article{SiC-2017-LIU-0, - title = {Stellar Origin of {\textsuperscript{15}}{{N-rich}} Presolar {{SiC}} Grains of Type {{AB}}: {{Supernovae}} with Explosive Hydrogen Burning}, - shorttitle = {Stellar {{Origin}} of {{15N-rich Presolar SiC Grains}} of {{Type AB}}}, - author = {Liu, Nan and Nittler, Larry R. and Pignatari, Marco and Alexander, C. M. O'D. and Wang, Jianhua}, - year = {2017}, + title = {Stellar Origin of {$^{15}$}{{N-rich}} Presolar {{SiC}} Grains of Type + {{AB}}: {{Supernovae}} with Explosive Hydrogen Burning}, + shorttitle = {Stellar {{Origin}} of {{15N-rich Presolar SiC Grains}} of {{Type + AB}}}, + author = {Liu, Nan and Nittler, Larry R. and Pignatari, Marco and Alexander, + C. M. O'D. and Wang, Jianhua}, + year = 2017, month = jun, journal = {The Astrophysical Journal Letters}, volume = {842}, @@ -1530,15 +3360,39 @@ @article{SiC-2017-LIU-0 issn = {2041-8205}, doi = {10.3847/2041-8213/aa74e5}, urldate = {2023-02-15}, - abstract = {We report C, N, and Si isotopic data for 59 highly 13C-enriched presolar submicron- to micron-sized SiC grains from the Murchison meteorite, including eight putative nova grains (PNGs) and 29 15N-rich (14N/15N {$\leq$} solar) AB grains, and their Mg--Al, S, and Ca--Ti isotope data when available. These 37 grains are enriched in 13C, 15N, and 26Al with the PNGs showing more extreme enhancements. The 15N-rich AB grains show systematically higher 26Al and 30Si excesses than the 14N-rich AB grains. Thus, we propose to divide the AB grains into groups 1 (14N/15N {$<$} solar) and 2 (14N/15N {$\geq$} solar). For the first time, we have obtained both S and Ti isotopic data for five AB1 grains and one PNG and found 32S and/or 50Ti enhancements. Interestingly, one AB1 grain had the largest 32S and 50Ti excesses, strongly suggesting a neutron-capture nucleosynthetic origin of the 32S excess and thus the initial presence of radiogenic 32Si (t1/2 = 153 years). More importantly, we found that the 15N and 26Al excesses of AB1 grains form a trend that extends to the region in the N--Al isotope plot occupied by C2 grains, strongly indicating a common stellar origin for both AB1 and C2 grains. Comparison of supernova models with the AB1 and C2 grain data indicates that these grains came from supernovae that experienced H ingestion into the He/C zones of their progenitors.}, - langid = {english} + abstract = {We report C, N, and Si isotopic data for 59 highly 13C-enriched + presolar submicron- to micron-sized SiC grains from the Murchison + meteorite, including eight putative nova grains (PNGs) and 29 + 15N-rich (14N/15N {$\leq$} solar) AB grains, and their Mg--Al, S, + and Ca--Ti isotope data when available. These 37 grains are + enriched in 13C, 15N, and 26Al with the PNGs showing more extreme + enhancements. The 15N-rich AB grains show systematically higher + 26Al and 30Si excesses than the 14N-rich AB grains. Thus, we + propose to divide the AB grains into groups 1 (14N/15N {$<$} solar) + and 2 (14N/15N {$\geq$} solar). For the first time, we have + obtained both S and Ti isotopic data for five AB1 grains and one + PNG and found 32S and/or 50Ti enhancements. Interestingly, one AB1 + grain had the largest 32S and 50Ti excesses, strongly suggesting a + neutron-capture nucleosynthetic origin of the 32S excess and thus + the initial presence of radiogenic 32Si (t1/2 = 153 years). More + importantly, we found that the 15N and 26Al excesses of AB1 grains + form a trend that extends to the region in the N--Al isotope plot + occupied by C2 grains, strongly indicating a common stellar origin + for both AB1 and C2 grains. Comparison of supernova models with the + AB1 and C2 grain data indicates that these grains came from + supernovae that experienced H ingestion into the He/C zones of + their progenitors.}, + langid = {english}, } @article{SiC-2017-LIU-1, - title = {J-Type Carbon Stars: {{A}} Dominant Source of {\textsuperscript{14}}{{N-rich}} Presolar {{SiC}} Grains of Type {{AB}}}, + title = {J-Type Carbon Stars: {{A}} Dominant Source of {$^{14}$} {{N-rich}} + Presolar {{SiC}} Grains of Type {{AB}}}, shorttitle = {J-Type {{Carbon Stars}}}, - author = {Liu, Nan and Stephan, Thomas and Boehnke, Patrick and Nittler, Larry R. and Alexander, C. M. O'D. and Wang, Jianhua and Davis, Andrew M. and Trappitsch, Reto and Pellin, Michael J.}, - year = {2017}, + author = {Liu, Nan and Stephan, Thomas and Boehnke, Patrick and Nittler, Larry + R. and Alexander, C. M. O'D. and Wang, Jianhua and Davis, Andrew M. + and Trappitsch, Reto and Pellin, Michael J.}, + year = 2017, month = jul, journal = {The Astrophysical Journal Letters}, volume = {844}, @@ -1548,15 +3402,36 @@ @article{SiC-2017-LIU-1 issn = {2041-8205}, doi = {10.3847/2041-8213/aa7d4c}, urldate = {2023-02-15}, - abstract = {We report Mo isotopic data of 27 new presolar SiC grains, including 12 14N-rich AB (14N/15N {$>$} 440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios when available. Direct comparison of the data for the MS grains, which came from low-mass asymptotic giant branch (AGB) stars with large s-process isotope enhancements, with the AB2 grain data demonstrates that AB2 grains show near-solar isotopic compositions and lack s-process enhancements. The near-normal Sr, Mo, and Ba isotopic compositions of AB2 grains clearly exclude born-again AGB stars, where the intermediate neutron-capture process (i-process) takes place, as their stellar source. On the other hand, low-mass CO novae and early R- and J-type carbon stars show 13C and 14N excesses but no s-process enhancements and are thus potential stellar sources of AB2 grains. Because both early R-type carbon stars and CO novae are rare objects, the abundant J-type carbon stars (10\%--15\% of all carbon stars) are thus likely to be a dominant source of AB2 grains.}, - langid = {english} + abstract = {We report Mo isotopic data of 27 new presolar SiC grains, + including 12 14N-rich AB (14N/15N {$>$} 440, AB2) and 15 mainstream + (MS) grains, and their correlated Sr and Ba isotope ratios when + available. Direct comparison of the data for the MS grains, which + came from low-mass asymptotic giant branch (AGB) stars with large + s-process isotope enhancements, with the AB2 grain data + demonstrates that AB2 grains show near-solar isotopic compositions + and lack s-process enhancements. The near-normal Sr, Mo, and Ba + isotopic compositions of AB2 grains clearly exclude born-again AGB + stars, where the intermediate neutron-capture process (i-process) + takes place, as their stellar source. On the other hand, low-mass + CO novae and early R- and J-type carbon stars show 13C and 14N + excesses but no s-process enhancements and are thus potential + stellar sources of AB2 grains. Because both early R-type carbon + stars and CO novae are rare objects, the abundant J-type carbon + stars (10\%--15\% of all carbon stars) are thus likely to be a + dominant source of AB2 grains.}, + langid = {english}, } @article{SiC-2017-LIU-2, - title = {Coordinated {{EDX}} and Micro-{{Raman}} Analysis of Presolar Silicon Carbide: {{A}} Novel, Nondestructive Method to Identify Rare Subgroup {{SiC}}}, - shorttitle = {Coordinated {{EDX}} and Micro-{{Raman}} Analysis of Presolar Silicon Carbide}, - author = {Liu, Nan and Steele, Andrew and Nittler, Larry R. and Stroud, Rhonda M. and De Gregorio, Bradley T. and Alexander, C. M. O'D. and Wang, Jianhua}, - year = {2017}, + title = {Coordinated {{EDX}} and Micro-{{Raman}} Analysis of Presolar Silicon + Carbide: {{A}} Novel, Nondestructive Method to Identify Rare Subgroup + {{SiC}}}, + shorttitle = {Coordinated {{EDX}} and Micro-{{Raman}} Analysis of Presolar + Silicon Carbide}, + author = {Liu, Nan and Steele, Andrew and Nittler, Larry R. and Stroud, Rhonda + M. and De Gregorio, Bradley T. and Alexander, C. M. O'D. and Wang, + Jianhua}, + year = 2017, journal = {Meteoritics \& Planetary Science}, volume = {52}, number = {12}, @@ -1564,102 +3439,292 @@ @article{SiC-2017-LIU-2 issn = {1945-5100}, doi = {10.1111/maps.12954}, urldate = {2023-02-15}, - abstract = {We report the development of a novel method to nondestructively identify presolar silicon carbide (SiC) grains with high initial 26Al/27Al ratios ({$>$}0.01) and extreme 13C-enrichments (12C/13C {$\leq$} 10) by backscattered electron-energy dispersive X-ray (EDX) and micro-Raman analyses. Our survey of a large number of presolar SiC demonstrates that (1) 80\% of core-collapse supernova and putative nova SiC can be identified by quantitative EDX and Raman analyses with {$>$}70\% confidence; (2) 90\% of presolar SiC are predominantly 3C-SiC, as indicated by their Raman transverse optical (TO) peak position and width; (3) presolar 3C-SiC with 12C/13C {$\leq$} 10 show lower Raman TO phonon frequencies compared to mainstream 3C-SiC. The downward shifted phonon frequencies of the 13C-enriched SiC with concomitant peak broadening are a natural consequence of isotope substitution. 13C-enriched SiC can therefore be identified by micro-Raman analysis; (4) larger shifts in the Raman TO peak position and width indicate deviations from the ideal 3C structure, including rare polytypes. Coordinated transmission electron microscopy analysis of one X and one mainstream SiC grain found them to be of 6H and 15R polytypes, respectively; (5) our correlated Raman and NanoSIMS study of mainstream SiC shows that high nitrogen content is a dominant factor in causing mainstream SiC Raman peak broadening without significant peak shifts; and (6) we found that the SiC condensation conditions in different stellar sites are astonishingly similar, except for X grains, which often condensed more rapidly and at higher atmospheric densities and temperatures, resulting in a higher fraction of grains with much downward shifted and broadened Raman TO peaks.}, - langid = {english} + abstract = {We report the development of a novel method to nondestructively + identify presolar silicon carbide (SiC) grains with high initial + 26Al/27Al ratios ({$>$}0.01) and extreme 13C-enrichments (12C/13C { + $\leq$} 10) by backscattered electron-energy dispersive X-ray (EDX) + and micro-Raman analyses. Our survey of a large number of presolar + SiC demonstrates that (1) 80\% of core-collapse supernova and + putative nova SiC can be identified by quantitative EDX and Raman + analyses with {$>$}70\% confidence; (2) 90\% of presolar SiC are + predominantly 3C-SiC, as indicated by their Raman transverse + optical (TO) peak position and width; (3) presolar 3C-SiC with + 12C/13C {$\leq$} 10 show lower Raman TO phonon frequencies compared + to mainstream 3C-SiC. The downward shifted phonon frequencies of + the 13C-enriched SiC with concomitant peak broadening are a natural + consequence of isotope substitution. 13C-enriched SiC can therefore + be identified by micro-Raman analysis; (4) larger shifts in the + Raman TO peak position and width indicate deviations from the ideal + 3C structure, including rare polytypes. Coordinated transmission + electron microscopy analysis of one X and one mainstream SiC grain + found them to be of 6H and 15R polytypes, respectively; (5) our + correlated Raman and NanoSIMS study of mainstream SiC shows that + high nitrogen content is a dominant factor in causing mainstream + SiC Raman peak broadening without significant peak shifts; and (6) + we found that the SiC condensation conditions in different stellar + sites are astonishingly similar, except for X grains, which often + condensed more rapidly and at higher atmospheric densities and + temperatures, resulting in a higher fraction of grains with much + downward shifted and broadened Raman TO peaks.}, + langid = {english}, } @article{SiC-2018-GYN-0, title = {Bonanza: {{An}} Extremely Large Dust Grain from a Supernova}, shorttitle = {Bonanza}, - author = {Gyngard, Frank and Jadhav, Manavi and Nittler, Larry R. and Stroud, Rhonda M. and Zinner, Ernst}, - year = {2018}, + author = {Gyngard, Frank and Jadhav, Manavi and Nittler, Larry R. and Stroud, + Rhonda M. and Zinner, Ernst}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {60--86}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.09.002}, urldate = {2023-02-15}, - abstract = {We report the morphology, microstructure, and isotopic composition of the largest SiC stardust grain known to have condensed from a supernova. The 25-{$\mu$}m diameter grain, termed Bonanza, was found in an acid-resistant residue of the Murchison meteorite. Grains of such large size have neither been observed around supernovae nor predicted to form in stellar environments. The large size of Bonanza has allowed the measurement of the isotopic composition of more elements in it than any other previous presolar grain, including: Li, B, C, N, Mg, Al, Si, S, Ca, Ti, Fe, and Ni. Bonanza exhibits large isotopic anomalies in the elements C, N, Mg, Si, Ca, Ti, Fe, and Ni typical of an astrophysical origin in ejecta of a Type II core-collapse supernova and comparable to those previously observed for other presolar SiC grains of type X. Additionally, we extracted multiple focused ion beam lift-out sections from different regions of the grain. Our transmission electron microscopy demonstrates that the crystalline order varies at the micrometer scale, and includes rare, higher order polytype domains (e.g., 15R). Analyses with STEM-EDS show Bonanza contains a heterogeneous distribution of subgrains with sizes ranging from {$<$}10nm to {$>$}100nm of Ti(N, C); Fe, Ni-rich grains with variable Fe:Ni; and (Al, Mg)N. Bonanza also has the highest ever inferred initial 26Al/27Al ratio, consistent with its supernova origin. This unique grain affords us the largest expanse of data, both microstructurally and isotopically, to compare with detailed calculations of nucleosynthesis and dust condensation in supernovae.}, + abstract = {We report the morphology, microstructure, and isotopic composition + of the largest SiC stardust grain known to have condensed from a + supernova. The 25-{$\mu$}m diameter grain, termed Bonanza, was + found in an acid-resistant residue of the Murchison meteorite. + Grains of such large size have neither been observed around + supernovae nor predicted to form in stellar environments. The large + size of Bonanza has allowed the measurement of the isotopic + composition of more elements in it than any other previous presolar + grain, including: Li, B, C, N, Mg, Al, Si, S, Ca, Ti, Fe, and Ni. + Bonanza exhibits large isotopic anomalies in the elements C, N, Mg, + Si, Ca, Ti, Fe, and Ni typical of an astrophysical origin in ejecta + of a Type II core-collapse supernova and comparable to those + previously observed for other presolar SiC grains of type X. + Additionally, we extracted multiple focused ion beam lift-out + sections from different regions of the grain. Our transmission + electron microscopy demonstrates that the crystalline order varies + at the micrometer scale, and includes rare, higher order polytype + domains (e.g., 15R). Analyses with STEM-EDS show Bonanza contains a + heterogeneous distribution of subgrains with sizes ranging from { + $<$}10nm to {$>$}100nm of Ti(N, C); Fe, Ni-rich grains with + variable Fe:Ni; and (Al, Mg)N. Bonanza also has the highest ever + inferred initial 26Al/27Al ratio, consistent with its supernova + origin. This unique grain affords us the largest expanse of data, + both microstructurally and isotopically, to compare with detailed + calculations of nucleosynthesis and dust condensation in + supernovae.}, langid = {english}, - keywords = {Isotopic anomalies,NanoSIMS,Nucleosynthesis,Presolar grains,Silicon carbide,Supernovae,Transmission electron microscopy} + keywords = {Isotopic anomalies,NanoSIMS,Nucleosynthesis,Presolar grains, + Silicon carbide,Supernovae,Transmission electron microscopy}, } @article{SiC-2018-GYN-1, - title = {Correlated Silicon and Titanium Isotopic Compositions of Presolar {{SiC}} Grains from the {{Murchison CM2}} Chondrite}, - author = {Gyngard, Frank and Amari, Sachiko and Zinner, Ernst and Marhas, Kuljeet Kaur}, - year = {2018}, + title = {Correlated Silicon and Titanium Isotopic Compositions of Presolar {{ + SiC}} Grains from the {{Murchison CM2}} Chondrite}, + author = {Gyngard, Frank and Amari, Sachiko and Zinner, Ernst and Marhas, + Kuljeet Kaur}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {145--161}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.09.031}, urldate = {2023-02-15}, - abstract = {We report correlated Si, and Ti isotopic compositions and elemental concentrations of 238 presolar SiC grains from the Murchison CM2 meteorite. Combined with measurements of the C and N isotopic compositions of these 238 grains, 220 were determined to be of type mainstream, 10 type AB, 4 type Y and 4 type Z. SiC grains of diameter {$\greaterequivlnt$}2.5{\textmu}m, to ensure enough material to attempt Ti measurements, were randomly chosen without any other prejudice. The Ti isotopic compositions of the majority of the grains are characterized by enrichments in 46Ti, 47Ti, 49Ti, and 50Ti relative to 48Ti, and show linear isotopic correlations indicative of galactic chemical evolution and neutron capture of the grains parent stars. The variability in the observed Ti signal as a function of depth in most of the grains indicates the presence of distinct subgrains, likely TiC that have been previously observed in TEM studies. Vandium-51 concentrations correlate with those of Ti, indicating V substitutes for Ti in the TiC matrix in many of the grains. No isotopic anomalies in 52Cr/53Cr ratios were observed, and Cr concentrations did not correlate with those of either Ti or V.}, + abstract = {We report correlated Si, and Ti isotopic compositions and + elemental concentrations of 238 presolar SiC grains from the + Murchison CM2 meteorite. Combined with measurements of the C and N + isotopic compositions of these 238 grains, 220 were determined to + be of type mainstream, 10 type AB, 4 type Y and 4 type Z. SiC + grains of diameter {$\greaterequivlnt$}2.5\textmu m, to ensure + enough material to attempt Ti measurements, were randomly chosen + without any other prejudice. The Ti isotopic compositions of the + majority of the grains are characterized by enrichments in 46Ti, + 47Ti, 49Ti, and 50Ti relative to 48Ti, and show linear isotopic + correlations indicative of galactic chemical evolution and neutron + capture of the grains parent stars. The variability in the observed + Ti signal as a function of depth in most of the grains indicates + the presence of distinct subgrains, likely TiC that have been + previously observed in TEM studies. Vandium-51 concentrations + correlate with those of Ti, indicating V substitutes for Ti in the + TiC matrix in many of the grains. No isotopic anomalies in + 52Cr/53Cr ratios were observed, and Cr concentrations did not + correlate with those of either Ti or V.}, langid = {english}, - keywords = {Asymptotic branch stars,Galactic chemical evolution,NanoSIMS,Nucleosynthesis,Presolar grains,Silicon carbide} + keywords = {Asymptotic branch stars,Galactic chemical evolution,NanoSIMS, + Nucleosynthesis,Presolar grains,Silicon carbide}, } @article{SiC-2018-HAE-0, - title = {Presolar Silicates in the Matrix and Fine-Grained Rims around Chondrules in Primitive {{CO3}}.0 Chondrites: {{Evidence}} for Pre-Accretionary Aqueous Alteration of the Rims in the Solar Nebula}, - shorttitle = {Presolar Silicates in the Matrix and Fine-Grained Rims around Chondrules in Primitive {{CO3}}.0 Chondrites}, - author = {Haenecour, Pierre and Floss, Christine and Zega, Thomas J. and Croat, Thomas K. and Wang, Alian and Jolliff, Bradley L. and Carpenter, Paul}, - year = {2018}, + title = {Presolar Silicates in the Matrix and Fine-Grained Rims around + Chondrules in Primitive {{CO3}}.0 Chondrites: {{Evidence}} for + Pre-Accretionary Aqueous Alteration of the Rims in the Solar Nebula}, + shorttitle = {Presolar Silicates in the Matrix and Fine-Grained Rims around + Chondrules in Primitive {{CO3}}.0 Chondrites}, + author = {Haenecour, Pierre and Floss, Christine and Zega, Thomas J. and Croat + , Thomas K. and Wang, Alian and Jolliff, Bradley L. and Carpenter, + Paul}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {379--405}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.06.004}, urldate = {2023-02-15}, - abstract = {To investigate the origin of fine-grained rims around chondrules (FGRs), we compared presolar grain abundances, elemental compositions and mineralogies in fine-grained interstitial matrix material and individual FGRs in the primitive CO3.0 chondrites Allan Hills A77307, LaPaz Icefield 031117 and Dominion Range 08006. The observation of similar overall O-anomalous ({$\sim$}155ppm) and C-anomalous grain abundances ({$\sim$}40ppm) in all three CO3.0 chondrites suggests that they all accreted from a nebular reservoir with similar presolar grain abundances. The presence of presolar silicate grains in FGRs combined with the observation of similar estimated porosity between interstitial matrix regions and FGRs in LAP 031117 and ALHA77307, as well as the identification of a composite FGR (a small rimmed chondrule within a larger chondrule rim) in ALHA77307, all provide evidence for a formation of FGRs by accretion of dust grains onto freely-floating chondrules in the solar nebula before their aggregation into their parent body asteroids. Our study also shows systematically lower abundances of presolar silicate grains in the FGRs than in the matrix regions of CO3 chondrites, while the abundances of SiC grains are the same in all areas, within errors. This trend differs from CR2 chondrites in which the presolar silicate abundances are higher in the FGRs than in the matrix, but similar to each other within 2{$\sigma$} errors. This observation combined with the identification of localized (micrometer-scaled) aqueous alteration in a FGR of LAP 031117 suggests that the lower abundance of presolar silicates in FGRs reflects pre-accretionary aqueous alteration of the fine-grained material in the FGRs. This pre-accretionary alteration could be due to either hydration and heating of freely floating rimmed chondrules in icy regions of the solar nebula or melted water ice associated with 26Al-related heating inside precursor planetesimals, followed by aggregation of FGRs into the CO chondrite parent-body.}, + abstract = {To investigate the origin of fine-grained rims around chondrules + (FGRs), we compared presolar grain abundances, elemental + compositions and mineralogies in fine-grained interstitial matrix + material and individual FGRs in the primitive CO3.0 chondrites + Allan Hills A77307, LaPaz Icefield 031117 and Dominion Range 08006. + The observation of similar overall O-anomalous ({$\sim$}155ppm) and + C-anomalous grain abundances ({$\sim$}40ppm) in all three CO3.0 + chondrites suggests that they all accreted from a nebular reservoir + with similar presolar grain abundances. The presence of presolar + silicate grains in FGRs combined with the observation of similar + estimated porosity between interstitial matrix regions and FGRs in + LAP 031117 and ALHA77307, as well as the identification of a + composite FGR (a small rimmed chondrule within a larger chondrule + rim) in ALHA77307, all provide evidence for a formation of FGRs by + accretion of dust grains onto freely-floating chondrules in the + solar nebula before their aggregation into their parent body + asteroids. Our study also shows systematically lower abundances of + presolar silicate grains in the FGRs than in the matrix regions of + CO3 chondrites, while the abundances of SiC grains are the same in + all areas, within errors. This trend differs from CR2 chondrites in + which the presolar silicate abundances are higher in the FGRs than + in the matrix, but similar to each other within 2{$\sigma$} errors. + This observation combined with the identification of localized + (micrometer-scaled) aqueous alteration in a FGR of LAP 031117 + suggests that the lower abundance of presolar silicates in FGRs + reflects pre-accretionary aqueous alteration of the fine-grained + material in the FGRs. This pre-accretionary alteration could be due + to either hydration and heating of freely floating rimmed + chondrules in icy regions of the solar nebula or melted water ice + associated with 26Al-related heating inside precursor planetesimals + , followed by aggregation of FGRs into the CO chondrite + parent-body.}, langid = {english}, - keywords = {Carbonaceous chondrites,Circumstellar grains,Early solar system history,Fine-grained chondrule rims,NanoSIMS,Nebular processes,Pre-accretionary alteration,Presolar grains,Solar Nebula,Stardust} + keywords = {Carbonaceous chondrites,Circumstellar grains,Early solar system + history,Fine-grained chondrule rims,NanoSIMS,Nebular processes, + Pre-accretionary alteration,Presolar grains,Solar Nebula,Stardust}, } @article{SiC-2018-HOP-0, - title = {{{NanoSIMS}} Isotope Studies of Rare Types of Presolar Silicon Carbide Grains from the {{Murchison}} Meteorite: {{Implications}} for Supernova Models and the Role of {{14C}}}, - shorttitle = {{{NanoSIMS}} Isotope Studies of Rare Types of Presolar Silicon Carbide Grains from the {{Murchison}} Meteorite}, - author = {Hoppe, Peter and Pignatari, Marco and Kodol{\'a}nyi, J{\'a}nos and Gr{\"o}ner, Elmar and Amari, Sachiko}, - year = {2018}, + title = {{{NanoSIMS}} Isotope Studies of Rare Types of Presolar Silicon + Carbide Grains from the {{Murchison}} Meteorite: {{Implications}} for + Supernova Models and the Role of {{14C}}}, + shorttitle = {{{NanoSIMS}} Isotope Studies of Rare Types of Presolar Silicon + Carbide Grains from the {{Murchison}} Meteorite}, + author = {Hoppe, Peter and Pignatari, Marco and Kodol{\'a}nyi, J{\'a}nos and + Gr{\"o}ner, Elmar and Amari, Sachiko}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {182--199}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.01.051}, urldate = {2023-02-15}, - abstract = {We have conducted a NanoSIMS ion imaging survey of about 1800 presolar silicon carbide (SiC) grains from the Murchison meteorite. A total of 21 supernova (SN) X grains, two SN C grains, and two putative nova grains were identified. Six particularly interesting grains, two X and C grains each and the two putative nova grains were subsequently studied in greater detail, namely, for C-, N-, Mg-Al-, Si-, S-, and Ca-Ti-isotopic compositions and for the initial presence of radioactive 26Al (half life 716,000yr), 32Si (half life 153yr), and 44Ti (half life 60yr). Their isotope data along with those of three X grains from the literature were compared with model predictions for 15M{$\odot$} and 25M{$\odot$} Type II supernovae (SNe). The best fits were found for 25M{$\odot$} SN models that consider for the He shell the temperature and density of a 15M{$\odot$} SN and ingestion of H into the He shell before the explosion. In these models a C- and Si-rich zone forms at the bottom of the He burning zone (C/Si zone). The region above the C/Si zone is termed the O/nova zone and exhibits the isotopic fingerprints of explosive H burning. Satisfactory fits of measured C-, N-, and Si-isotopic compositions and of 26Al/27Al ratios require small-scale mixing of matter originating from a region extending over 0.2M{$\odot$} for X and C grains and over 0.4M{$\odot$} for one of the putative nova grains, involving matter from a thin Si-rich layer slightly below the C/Si zone, the C/Si zone, and the O/nova zone. Simultaneous fitting of 14N/15N and 26Al/27Al requires a C-N fractionation of a factor of 50 during SiC condensation. This leads to preferential incorporation of radioactive 14C (half life 5700yr) over directly produced 14N and can account for the 14N/15N along with 26Al/27Al ratios as observed in the SiC grains. The good fit for one of the putative nova grains along with its high 26Al/27Al points towards a SN origin and supports previous suggestions that some grains classified as nova grains might be from SNe. Apparent problems with the small-scale mixing scheme considered here are C/O ratios that are mostly {$<$}1 if C-, N-, and Si-isotopic compositions and 26Al/27Al ratios are simultaneously matched, underproduction of 32Si, and overproduction of 44Ti. This confirms the limitations of one-dimensional hydrodynamical models for H ingestion and stresses the need to better study the convective-boundary mixing mechanisms at the bottom of the convective He shell in massive star progenitors. This is crucial to define the effective size of the C/Si zone formed by the SN shock. The comparison between the Si isotope data of the SN grains and the models gives a hint that the predicted 30Si is too high at the bottom of the He burning shell.}, + abstract = {We have conducted a NanoSIMS ion imaging survey of about 1800 + presolar silicon carbide (SiC) grains from the Murchison meteorite. + A total of 21 supernova (SN) X grains, two SN C grains, and two + putative nova grains were identified. Six particularly interesting + grains, two X and C grains each and the two putative nova grains + were subsequently studied in greater detail, namely, for C-, N-, + Mg-Al-, Si-, S-, and Ca-Ti-isotopic compositions and for the + initial presence of radioactive 26Al (half life 716,000yr), 32Si + (half life 153yr), and 44Ti (half life 60yr). Their isotope data + along with those of three X grains from the literature were + compared with model predictions for 15M{$\odot$} and 25M{$\odot$} + Type II supernovae (SNe). The best fits were found for 25M{$\odot$} + SN models that consider for the He shell the temperature and + density of a 15M{$\odot$} SN and ingestion of H into the He shell + before the explosion. In these models a C- and Si-rich zone forms + at the bottom of the He burning zone (C/Si zone). The region above + the C/Si zone is termed the O/nova zone and exhibits the isotopic + fingerprints of explosive H burning. Satisfactory fits of measured + C-, N-, and Si-isotopic compositions and of 26Al/27Al ratios + require small-scale mixing of matter originating from a region + extending over 0.2M{$\odot$} for X and C grains and over 0.4M{$ + \odot$} for one of the putative nova grains, involving matter from + a thin Si-rich layer slightly below the C/Si zone, the C/Si zone, + and the O/nova zone. Simultaneous fitting of 14N/15N and 26Al/27Al + requires a C-N fractionation of a factor of 50 during SiC + condensation. This leads to preferential incorporation of + radioactive 14C (half life 5700yr) over directly produced 14N and + can account for the 14N/15N along with 26Al/27Al ratios as observed + in the SiC grains. The good fit for one of the putative nova grains + along with its high 26Al/27Al points towards a SN origin and + supports previous suggestions that some grains classified as nova + grains might be from SNe. Apparent problems with the small-scale + mixing scheme considered here are C/O ratios that are mostly {$<$}1 + if C-, N-, and Si-isotopic compositions and 26Al/27Al ratios are + simultaneously matched, underproduction of 32Si, and overproduction + of 44Ti. This confirms the limitations of one-dimensional + hydrodynamical models for H ingestion and stresses the need to + better study the convective-boundary mixing mechanisms at the + bottom of the convective He shell in massive star progenitors. This + is crucial to define the effective size of the C/Si zone formed by + the SN shock. The comparison between the Si isotope data of the SN + grains and the models gives a hint that the predicted 30Si is too + high at the bottom of the He burning shell.}, langid = {english}, - keywords = {Meteorites,Presolar grains,Secondary ion mass spectrometry,Silicon carbide,Supernovae} + keywords = {Meteorites,Presolar grains,Secondary ion mass spectrometry,Silicon + carbide,Supernovae}, } @article{SiC-2018-KOD-0, - title = {Iron and Nickel Isotope Compositions of Presolar Silicon Carbide Grains from Supernovae}, - author = {Kodol{\'a}nyi, J{\'a}nos and Stephan, Thomas and Trappitsch, Reto and Hoppe, Peter and Pignatari, Marco and Davis, Andrew M. and Pellin, Michael J.}, - year = {2018}, + title = {Iron and Nickel Isotope Compositions of Presolar Silicon Carbide + Grains from Supernovae}, + author = {Kodol{\'a}nyi, J{\'a}nos and Stephan, Thomas and Trappitsch, Reto + and Hoppe, Peter and Pignatari, Marco and Davis, Andrew M. and Pellin + , Michael J.}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {127--144}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.05.029}, urldate = {2023-02-15}, - abstract = {We report the carbon, silicon, iron, and nickel isotope compositions of twenty-five presolar SiC grains of mostly supernova (SN) origin. The iron and nickel isotope compositions were measured with the new Chicago Instrument for Laser Ionization, CHILI, which allows the analysis of all iron and nickel isotopes without the isobaric interferences that plagued previous measurements with the NanoSIMS. Despite terrestrial iron and nickel contamination, significant isotopic anomalies in 54Fe/56Fe, 57Fe/56Fe, 60Ni/58Ni, 61Ni/58Ni, 62Ni/58Ni, and 64Ni/58Ni were detected in nine SN grains (of type X). Combined multi-isotope data of three grains with the largest nickel isotope anomalies ({$>$}100‰ or {$<-$}100‰ in at least one isotope ratio, when expressed as deviation from the solar value) are compared with the predictions of two SN models, one with and one without hydrogen ingestion in the He shell prior to SN explosion. One grain's carbon-silicon-iron-nickel isotope composition is consistent with the prediction of the model without hydrogen ingestion, whereas the other two grains' isotope anomalies could not be reproduced using either SN models. The discrepancies between the measured isotope compositions and model predictions may indicate element fractionation in the SN ejecta prior to or during grain condensation, and reiterate the need for three-dimensional SN models.}, + abstract = {We report the carbon, silicon, iron, and nickel isotope + compositions of twenty-five presolar SiC grains of mostly supernova + (SN) origin. The iron and nickel isotope compositions were measured + with the new Chicago Instrument for Laser Ionization, CHILI, which + allows the analysis of all iron and nickel isotopes without the + isobaric interferences that plagued previous measurements with the + NanoSIMS. Despite terrestrial iron and nickel contamination, + significant isotopic anomalies in 54Fe/56Fe, 57Fe/56Fe, 60Ni/58Ni, + 61Ni/58Ni, 62Ni/58Ni, and 64Ni/58Ni were detected in nine SN grains + (of type X). Combined multi-isotope data of three grains with the + largest nickel isotope anomalies ({$>$}100‰ or {$<$}-100‰ in at + least one isotope ratio, when expressed as deviation from the solar + value) are compared with the predictions of two SN models, one with + and one without hydrogen ingestion in the He shell prior to SN + explosion. One grain's carbon-silicon-iron-nickel isotope + composition is consistent with the prediction of the model without + hydrogen ingestion, whereas the other two grains' isotope anomalies + could not be reproduced using either SN models. The discrepancies + between the measured isotope compositions and model predictions may + indicate element fractionation in the SN ejecta prior to or during + grain condensation, and reiterate the need for three-dimensional SN + models.}, langid = {english}, - keywords = {Chicago instrument for laser ionization,Iron isotopes,Nickel isotopes,Nucleosynthesis,Supernova} + keywords = {Chicago instrument for laser ionization,Iron isotopes,Nickel + isotopes,Nucleosynthesis,Supernova}, } @article{SiC-2018-LEI-0, - title = {A Study of Presolar Material in Hydrated Lithic Clasts from Metal-rich Carbonaceous Chondrites}, + title = {A Study of Presolar Material in Hydrated Lithic Clasts from + Metal-Rich Carbonaceous Chondrites}, author = {Leitner, Jan and Hoppe, Peter and Zipfel, Jutta}, - year = {2018}, + year = 2018, month = feb, journal = {Meteoritics \& Planetary Science}, volume = {53}, @@ -1668,15 +3733,43 @@ @article{SiC-2018-LEI-0 issn = {1086-9379, 1945-5100}, doi = {10.1111/maps.12994}, urldate = {2025-03-24}, - abstract = {Abstract We report on the investigation of presolar grain inventories of hydrated lithic clasts in three metal-rich carbonaceous chondrites from the CR clan, Acfer 182 ( CH 3), Isheyevo ( CH 3/ CB b 3), and Lewis Cliff ( LEW ) 85332 (C3-un), as well as the carbon- and nitrogen-isotopic compositions of the fine-grained clast material. Eleven presolar silicate grains as well as nine presolar silicon carbide (SiC) grains were identified in the clasts. Presolar silicate abundances range from 4 to 22 parts per million (ppm), significantly lower than in pristine meteorites and interplanetary dust particles ( IDP ), and comparable to recent findings for CM 2s and CR 2 interchondrule matrix. SiC concentrations lie between 9 and 23~ppm, and are comparable to the values for CI , CM , and CR chondrites. The results of our investigation suggest similar alteration pathways for the clast material, the interchondrule matrix of the CR 2 chondrites, and the fine-grained fraction of CM 2 chondrites. Fine-grained matter of all three meteorites contains moderate to high 15 N-enrichments ({\textasciitilde}50‰~{$\leq~\delta$} 15 N~{$\leq~$}{\textasciitilde}1600‰) compared to the terrestrial value, indicating the presence of primitive organic material. We observed no correlation between 15 N-enrichments and presolar dust concentrations in the clasts. This is in contrast to the findings from a suite of primitive IDP s, which display in several cases enhanced bulk 15 N/ 14 N ratios and high presolar grain abundances of several hundred or even thousand ppm. The bulk 15 N/ 14 N ratios of the clasts are comparable to the range for primitive IDP s, suggesting a nitrogen carrier less susceptible to destruction by aqueous alteration than silicate stardust.}, - copyright = {http://onlinelibrary.wiley.com/termsAndConditions\#vor}, - langid = {english} + abstract = {Abstract We report on the investigation of presolar grain + inventories of hydrated lithic clasts in three metal-rich + carbonaceous chondrites from the CR clan, Acfer 182 ( CH 3), + Isheyevo ( CH 3/ CB b 3), and Lewis Cliff ( LEW ) 85332 (C3-un), as + well as the carbon- and nitrogen-isotopic compositions of the + fine-grained clast material. Eleven presolar silicate grains as + well as nine presolar silicon carbide (SiC) grains were identified + in the clasts. Presolar silicate abundances range from 4 to 22 + parts per million (ppm), significantly lower than in pristine + meteorites and interplanetary dust particles ( IDP ), and + comparable to recent findings for CM 2s and CR 2 interchondrule + matrix. SiC concentrations lie between 9 and 23 ppm, and are + comparable to the values for CI , CM , and CR chondrites. The + results of our investigation suggest similar alteration pathways + for the clast material, the interchondrule matrix of the CR 2 + chondrites, and the fine-grained fraction of CM 2 chondrites. + Fine-grained matter of all three meteorites contains moderate to + high 15 N-enrichments (\textasciitilde 50‰ {$\leq$}\textasciitilde{ + $\delta$} 15 N {$\leq$}\textasciitilde\textasciitilde 1600‰) + compared to the terrestrial value, indicating the presence of + primitive organic material. We observed no correlation between 15 + N-enrichments and presolar dust concentrations in the clasts. This + is in contrast to the findings from a suite of primitive IDP s, + which display in several cases enhanced bulk 15 N/ 14 N ratios and + high presolar grain abundances of several hundred or even thousand + ppm. The bulk 15 N/ 14 N ratios of the clasts are comparable to the + range for primitive IDP s, suggesting a nitrogen carrier less + susceptible to destruction by aqueous alteration than silicate + stardust.}, + langid = {english}, } @article{SiC-2018-LIU-0, title = {Late Formation of Silicon Carbide in Type {{II}} Supernovae}, - author = {Liu, Nan and Nittler, Larry R. and Alexander, Conel M. O'D. and Wang, Jianhua}, - year = {2018}, + author = {Liu, Nan and Nittler, Larry R. and Alexander, Conel M. O'D. and Wang + , Jianhua}, + year = 2018, month = jan, journal = {Science Advances}, volume = {4}, @@ -1685,13 +3778,27 @@ @article{SiC-2018-LIU-0 publisher = {American Association for the Advancement of Science}, doi = {10.1126/sciadv.aao1054}, urldate = {2023-02-15}, - abstract = {We have found that individual presolar silicon carbide (SiC) dust grains from supernovae show a positive correlation between 49Ti and 28Si excesses, which is attributed to the radioactive decay of the short-lived (t{$\frac{1}{2}$} = 330 days) 49V to 49Ti in the inner highly 28Si-rich Si/S zone. The 49V-49Ti chronometer shows that these supernova SiC dust grains formed at least 2 years after their parent stars exploded. This result supports recent dust condensation calculations that predict a delayed formation of carbonaceous and SiC grains in supernovae. The astronomical observation of continuous buildup of dust in supernovae over several years can, therefore, be interpreted as a growing addition of C-rich dust to the dust reservoir in supernovae.} + abstract = {We have found that individual presolar silicon carbide (SiC) dust + grains from supernovae show a positive correlation between 49Ti and + 28Si excesses, which is attributed to the radioactive decay of the + short-lived (t{$\frac{1}{2}$} = 330 days) 49V to 49Ti in the inner + highly 28Si-rich Si/S zone. The 49V-49Ti chronometer shows that + these supernova SiC dust grains formed at least 2 years after their + parent stars exploded. This result supports recent dust + condensation calculations that predict a delayed formation of + carbonaceous and SiC grains in supernovae. The astronomical + observation of continuous buildup of dust in supernovae over + several years can, therefore, be interpreted as a growing addition + of C-rich dust to the dust reservoir in supernovae.}, } @article{SiC-2018-LIU-1, - title = {Common Occurrence of Explosive Hydrogen Burning in Type {{II}} Supernovae}, - author = {Liu, Nan and Stephan, Thomas and Boehnke, Patrick and Nittler, Larry R. and Meyer, Bradley S. and Alexander, C. M. O'D. and Davis, Andrew M. and Trappitsch, Reto and Pellin, Michael J.}, - year = {2018}, + title = {Common Occurrence of Explosive Hydrogen Burning in Type {{II}} + Supernovae}, + author = {Liu, Nan and Stephan, Thomas and Boehnke, Patrick and Nittler, Larry + R. and Meyer, Bradley S. and Alexander, C. M. O'D. and Davis, Andrew + M. and Trappitsch, Reto and Pellin, Michael J.}, + year = 2018, month = mar, journal = {The Astrophysical Journal}, volume = {855}, @@ -1701,31 +3808,89 @@ @article{SiC-2018-LIU-1 issn = {0004-637X}, doi = {10.3847/1538-4357/aaab4e}, urldate = {2023-02-15}, - abstract = {We report Mo isotopic data for 16 15N-rich presolar SiC grains of type AB (14N/15N {$<$} solar, AB1) and their correlated Sr and Ba isotope ratios when available. Of the 16 AB1 grains, 8 show s-process Mo isotopic compositions, together with s-process Ba and/or Sr isotopic compositions. We found that a higher percentage of AB1 grains show anomalous isotopic compositions than that of AB2 grains (14N/15N {$>$} solar), thus providing further support to the division of the two AB subgroups recently proposed by Liu et al., who showed that AB1 grains most likely originated from Type II supernovae (SNe) with explosive H burning. Comparison of the Sr, Mo, and Ba isotopic compositions of the AB1 grains with SN model predictions indicates that the s-process isotopic compositions of AB1 grains resulted from neutron-capture processes occurring during the progenitor massive stars' pre-SN evolution rather than from an explosive neutron-capture process. In addition, the observations of (1) explosive H burning occurring in the C-rich regions of the progenitor SNe of X grains as suggested by the isotopic compositions of X grains, and (2) explosive H burning occurring both at the bottom of the He/C zone and at the top of the He/N zone as suggested by model simulations, imply that explosive H burning is a common phenomenon in outer SN zones.}, - langid = {english} + abstract = {We report Mo isotopic data for 16 15N-rich presolar SiC grains of + type AB (14N/15N {$<$} solar, AB1) and their correlated Sr and Ba + isotope ratios when available. Of the 16 AB1 grains, 8 show + s-process Mo isotopic compositions, together with s-process Ba + and/or Sr isotopic compositions. We found that a higher percentage + of AB1 grains show anomalous isotopic compositions than that of AB2 + grains (14N/15N {$>$} solar), thus providing further support to the + division of the two AB subgroups recently proposed by Liu et al., + who showed that AB1 grains most likely originated from Type II + supernovae (SNe) with explosive H burning. Comparison of the Sr, Mo + , and Ba isotopic compositions of the AB1 grains with SN model + predictions indicates that the s-process isotopic compositions of + AB1 grains resulted from neutron-capture processes occurring during + the progenitor massive stars' pre-SN evolution rather than from an + explosive neutron-capture process. In addition, the observations of + (1) explosive H burning occurring in the C-rich regions of the + progenitor SNe of X grains as suggested by the isotopic + compositions of X grains, and (2) explosive H burning occurring + both at the bottom of the He/C zone and at the top of the He/N zone + as suggested by model simulations, imply that explosive H burning + is a common phenomenon in outer SN zones.}, + langid = {english}, } @article{SiC-2018-NGU-0, - title = {Titanium Isotopic Compositions of Rare Presolar {{SiC}} Grain Types from the {{Murchison}} Meteorite}, - author = {Nguyen, Ann N. and Nittler, Larry R. and Alexander, C. M. O'D. and Hoppe, Peter}, - year = {2018}, + title = {Titanium Isotopic Compositions of Rare Presolar {{SiC}} Grain Types + from the {{Murchison}} Meteorite}, + author = {Nguyen, Ann N. and Nittler, Larry R. and Alexander, C. M. O'D. and + Hoppe, Peter}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {162--181}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.02.026}, urldate = {2023-02-15}, - abstract = {We report the Ti isotopic compositions of 8 mainstream, 22 Y, 9 Z, and 26 AB presolar SiC grains from two SiC-rich residues of the Murchison CM2 meteorite together with Si, C and some Mg-Al isotopic data for the same grains. Mainstream, Y and Z grains are believed to originate in asymptotic giant branch (AGB) stars of varying metallicities, but the stellar sources of AB grains are poorly understood. We find that the 46,47,49Ti/48Ti ratios are correlated with 29Si/28Si for all of the grain types, indicating that these ratios are mainly dominated by Galactic chemical evolution (GCE). The mainstream, Y and Z grains all show enrichments in 50Ti from neutron capture nucleosynthesis. However, AGB models predict smaller excesses in 50Ti (and 49Ti) than are observed in these grains. For Z grains and especially for Y grains, the enhancement of 50Ti is greater than the enhancement in 30Si, indicating that the 13C neutron source produced a greater total fluence of neutrons than the 22Ne source in the low metallicity parent AGB stars. The Z grains plot below the mainstream correlation lines at more 48Ti- and 28Si-rich compositions in plots of 46,47,49Ti/48Ti vs. 29Si/28Si. On the other hand, the Y grains plot close to the mainstream correlation line. This could imply that the Ti isotopes evolved non-linearly at metallicities below {$\sim$}1/3 solar. The AB grains in this study have Ti isotopic compositions that fall along correlation lines defined by the mainstream grains, suggesting origins in close to solar metallicity stars. However, these grains fall below the mainstream correlation lines in plots of 46,49,50Ti/48Ti vs. 29Si/28Si and do not show enhancements in 50Ti, indicating that their parent stars did not undergo significant s-process nucleosynthesis. These data support origins of AB grains in J-type C stars rather than born-again AGB stars that undergo s-process nucleosynthesis. AB grains that do not have 50Ti excesses may provide the best measure of Si and Ti isotope GCE since their parent stars were less affected by s-process nucleosynthesis than the mainstream grains.}, + abstract = {We report the Ti isotopic compositions of 8 mainstream, 22 Y, 9 Z, + and 26 AB presolar SiC grains from two SiC-rich residues of the + Murchison CM2 meteorite together with Si, C and some Mg-Al isotopic + data for the same grains. Mainstream, Y and Z grains are believed + to originate in asymptotic giant branch (AGB) stars of varying + metallicities, but the stellar sources of AB grains are poorly + understood. We find that the 46,47,49Ti/48Ti ratios are correlated + with 29Si/28Si for all of the grain types, indicating that these + ratios are mainly dominated by Galactic chemical evolution (GCE). + The mainstream, Y and Z grains all show enrichments in 50Ti from + neutron capture nucleosynthesis. However, AGB models predict + smaller excesses in 50Ti (and 49Ti) than are observed in these + grains. For Z grains and especially for Y grains, the enhancement + of 50Ti is greater than the enhancement in 30Si, indicating that + the 13C neutron source produced a greater total fluence of neutrons + than the 22Ne source in the low metallicity parent AGB stars. The Z + grains plot below the mainstream correlation lines at more 48Ti- + and 28Si-rich compositions in plots of 46,47,49Ti/48Ti vs. + 29Si/28Si. On the other hand, the Y grains plot close to the + mainstream correlation line. This could imply that the Ti isotopes + evolved non-linearly at metallicities below {$\sim$}1/3 solar. The + AB grains in this study have Ti isotopic compositions that fall + along correlation lines defined by the mainstream grains, + suggesting origins in close to solar metallicity stars. However, + these grains fall below the mainstream correlation lines in plots + of 46,49,50Ti/48Ti vs. 29Si/28Si and do not show enhancements in + 50Ti, indicating that their parent stars did not undergo + significant s-process nucleosynthesis. These data support origins + of AB grains in J-type C stars rather than born-again AGB stars + that undergo s-process nucleosynthesis. AB grains that do not have + 50Ti excesses may provide the best measure of Si and Ti isotope GCE + since their parent stars were less affected by s-process + nucleosynthesis than the mainstream grains.}, langid = {english}, - keywords = {Circumstellar grains,Galactic chemical evolution,Nucleosynthesis,Stars} + keywords = {Circumstellar grains,Galactic chemical evolution,Nucleosynthesis, + Stars}, } @article{SiC-2018-NIT-0, - title = {High Abundances of Presolar Grains and {{15N-rich}} Organic Matter in {{CO3}}.0 Chondrite {{Dominion Range}} 08006}, - author = {Nittler, Larry R. and Alexander, C. M. O'D. and Davidson, Jemma and Riebe, My E. I. and Stroud, Rhonda M. and Wang, Jianhua}, - year = {2018}, + title = {High Abundances of Presolar Grains and {{15N-rich}} Organic Matter in + {{CO3}}.0 Chondrite {{Dominion Range}} 08006}, + author = {Nittler, Larry R. and Alexander, C. M. O'D. and Davidson, Jemma and + Riebe, My E. I. and Stroud, Rhonda M. and Wang, Jianhua}, + year = 2018, month = apr, journal = {Geochimica et Cosmochimica Acta}, volume = {226}, @@ -1733,49 +3898,139 @@ @article{SiC-2018-NIT-0 issn = {0016-7037}, doi = {10.1016/j.gca.2018.01.038}, urldate = {2023-02-15}, - abstract = {NanoSIMS C-, N-, and O-isotopic mapping of matrix in CO3.0 chondrite Dominion Range (DOM) 08006 revealed it to have in its matrix the highest abundance of presolar O-rich grains (257 +76/-96\,ppm, 2{$\sigma$}) of any meteorite. It also has a matrix abundance of presolar SiC of 35 (+25/-17, 2{$\sigma$}) ppm, similar to that seen across primitive chondrite classes. This provides additional support to bulk isotopic and petrologic evidence that DOM 08006 is the most primitive known CO meteorite. Transmission electron microscopy of five presolar silicate grains revealed one to have a composite mineralogy similar to larger amoeboid olivine aggregates and consistent with equilibrium condensation, two non-stoichiometric amorphous grains, and two olivine grains, though one is identified as such solely based on its composition. We also found insoluble organic matter (IOM) to be present primarily as sub-micron inclusions with ranges of C- and N-isotopic anomalies similar to those seen in primitive CR chondrites and interplanetary dust particles. In contrast to other primitive extraterrestrial materials, H isotopic imaging showed normal and homogeneous D/H. Most likely, DOM 08006 and other CO chondrites accreted a similar complement of primitive and isotopically anomalous organic matter to that found in other chondrite classes and IDPs, but the very limited amount of thermal metamorphism experienced by DOM 08006 has caused loss of D-rich organic moieties, while not substantially affecting either the molecular carriers of C and N anomalies or most inorganic phases in the meteorite. One C-rich grain that was highly depleted in 13C and 15N was identified; we propose it originated in the Sun's parental molecular cloud.}, + abstract = {NanoSIMS C-, N-, and O-isotopic mapping of matrix in CO3.0 + chondrite Dominion Range (DOM) 08006 revealed it to have in its + matrix the highest abundance of presolar O-rich grains (257 +76/-96 + \,ppm, 2{$\sigma$}) of any meteorite. It also has a matrix + abundance of presolar SiC of 35 (+25/-17, 2{$\sigma$}) ppm, similar + to that seen across primitive chondrite classes. This provides + additional support to bulk isotopic and petrologic evidence that + DOM 08006 is the most primitive known CO meteorite. Transmission + electron microscopy of five presolar silicate grains revealed one + to have a composite mineralogy similar to larger amoeboid olivine + aggregates and consistent with equilibrium condensation, two + non-stoichiometric amorphous grains, and two olivine grains, though + one is identified as such solely based on its composition. We also + found insoluble organic matter (IOM) to be present primarily as + sub-micron inclusions with ranges of C- and N-isotopic anomalies + similar to those seen in primitive CR chondrites and interplanetary + dust particles. In contrast to other primitive extraterrestrial + materials, H isotopic imaging showed normal and homogeneous D/H. + Most likely, DOM 08006 and other CO chondrites accreted a similar + complement of primitive and isotopically anomalous organic matter + to that found in other chondrite classes and IDPs, but the very + limited amount of thermal metamorphism experienced by DOM 08006 has + caused loss of D-rich organic moieties, while not substantially + affecting either the molecular carriers of C and N anomalies or + most inorganic phases in the meteorite. One C-rich grain that was + highly depleted in 13C and 15N was identified; we propose it + originated in the Sun's parental molecular cloud.}, langid = {english}, - keywords = {Carbonaceous chondrites,Early solar system history,Isotopic anomalies,NanoSIMS,Nebular processes,Organic matter,Presolar grains Stardust,Solar Nebula} + keywords = {Carbonaceous chondrites,Early solar system history,Isotopic + anomalies,NanoSIMS,Nebular processes,Organic matter,Presolar grains + Stardust,Solar Nebula}, } @article{SiC-2018-STE-0, - title = {Strontium and Barium Isotopes in Presolar Silicon Carbide Grains Measured with {{CHILI---two}} Types of {{X}} Grains}, - author = {Stephan, Thomas and Trappitsch, Reto and Davis, Andrew M. and Pellin, Michael J. and Rost, Detlef and Savina, Michael R. and Jadhav, Manavi and Kelly, Christopher H. and Gyngard, Frank and Hoppe, Peter and Dauphas, Nicolas}, - year = {2018}, + title = {Strontium and Barium Isotopes in Presolar Silicon Carbide Grains + Measured with {{CHILI---two}} Types of {{X}} Grains}, + author = {Stephan, Thomas and Trappitsch, Reto and Davis, Andrew M. and Pellin + , Michael J. and Rost, Detlef and Savina, Michael R. and Jadhav, + Manavi and Kelly, Christopher H. and Gyngard, Frank and Hoppe, Peter + and Dauphas, Nicolas}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {109--126}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.05.001}, urldate = {2023-02-15}, - abstract = {We used CHILI, the Chicago Instrument for Laser Ionization, a new resonance ionization mass spectrometer developed for isotopic analysis of small samples, to analyze strontium, zirconium, and barium isotopes in 22 presolar silicon carbide grains. Twenty of the grains showed detectable strontium and barium, but none of the grains had enough zirconium to be detected with CHILI. Nine grains were excluded from further consideration since they showed very little signals ({$<$}1000 counts) for strontium as well as for barium. Among the 11 remaining grains, we found three X grains. The discovery of three supernova grains among only 22 grains was fortuitous, because only {$\sim$}1\% of presolar silicon carbide grains are type X, but was confirmed by silicon isotopic measurements of grain residues with NanoSIMS. While one of the X grains showed strontium and barium isotope patterns expected for supernova grains, the two other supernova grains have 87Sr/86Sr{$<$}0.5, values never observed in any natural sample before. From their silicon isotope ratios, the latter two grains can be classified as X2 grains, while the former grain belongs to the more common X1 group. The differences of these grains in strontium and barium isotopic composition constrain their individual formation conditions in Type II supernovae.}, + abstract = {We used CHILI, the Chicago Instrument for Laser Ionization, a new + resonance ionization mass spectrometer developed for isotopic + analysis of small samples, to analyze strontium, zirconium, and + barium isotopes in 22 presolar silicon carbide grains. Twenty of + the grains showed detectable strontium and barium, but none of the + grains had enough zirconium to be detected with CHILI. Nine grains + were excluded from further consideration since they showed very + little signals ({$<$}1000 counts) for strontium as well as for + barium. Among the 11 remaining grains, we found three X grains. The + discovery of three supernova grains among only 22 grains was + fortuitous, because only {$\sim$}1\% of presolar silicon carbide + grains are type X, but was confirmed by silicon isotopic + measurements of grain residues with NanoSIMS. While one of the X + grains showed strontium and barium isotope patterns expected for + supernova grains, the two other supernova grains have 87Sr/86Sr{$<$ + } 0.5, values never observed in any natural sample before. From + their silicon isotope ratios, the latter two grains can be + classified as X2 grains, while the former grain belongs to the more + common X1 group. The differences of these grains in strontium and + barium isotopic composition constrain their individual formation + conditions in Type II supernovae.}, langid = {english}, - keywords = {Barium isotopes,Nucleosynthesis,Presolar grains,Resonance ionization mass spectrometry (RIMS),Silicon carbide,Strontium isotopes,Supernovae} + keywords = {Barium isotopes,Nucleosynthesis,Presolar grains,Resonance + ionization mass spectrometry (RIMS),Silicon carbide,Strontium + isotopes,Supernovae}, } @article{SiC-2018-TRA-0, - title = {Simultaneous Iron and Nickel Isotopic Analyses of Presolar Silicon Carbide Grains}, - author = {Trappitsch, Reto and Stephan, Thomas and Savina, Michael R. and Davis, Andrew M. and Pellin, Michael J. and Rost, Detlef and Gyngard, Frank and Gallino, Roberto and Bisterzo, Sara and Cristallo, Sergio and Dauphas, Nicolas}, - year = {2018}, + title = {Simultaneous Iron and Nickel Isotopic Analyses of Presolar Silicon + Carbide Grains}, + author = {Trappitsch, Reto and Stephan, Thomas and Savina, Michael R. and + Davis, Andrew M. and Pellin, Michael J. and Rost, Detlef and Gyngard, + Frank and Gallino, Roberto and Bisterzo, Sara and Cristallo, Sergio + and Dauphas, Nicolas}, + year = 2018, month = jan, journal = {Geochimica et Cosmochimica Acta}, - series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{A Special}} Issue for {{Ernst K}}. {{Zinner}}}, + series = {Astrophysical {{Implications}} of {{Extraterrestrial Materials}}: {{ + A Special}} Issue for {{Ernst K}}. {{Zinner}}}, volume = {221}, pages = {87--108}, issn = {0016-7037}, doi = {10.1016/j.gca.2017.05.031}, urldate = {2023-02-15}, - abstract = {Aside from recording stellar nucleosynthesis, a few elements in presolar grains can also provide insights into the galactic chemical evolution (GCE) of nuclides. We have studied the carbon, silicon, iron, and nickel isotopic compositions of presolar silicon carbide (SiC) grains from asymptotic giant branch (AGB) stars to better understand GCE. Since only the neutron-rich nuclides in these grains have been heavily influenced by the parent star, the neutron-poor nuclides serve as GCE proxies. Using CHILI, a new resonance ionization mass spectrometry (RIMS) instrument, we measured 74 presolar SiC grains for all iron and nickel isotopes. With the CHARISMA instrument, 13 presolar SiC grains were analyzed for iron isotopes. All grains were also measured by NanoSIMS for their carbon and silicon isotopic compositions. A comparison of the measured neutron-rich isotopes with models for AGB star nucleosynthesis shows that our measurements are consistent with AGB star predictions for low-mass stars between half-solar and solar metallicity. Furthermore, our measurements give an indication on the 22Ne({$\alpha$},n)25Mg reaction rate. In terms of GCE, we find that the GCE-dominated iron and nickel isotope ratios, 54Fe/56Fe and 60Ni/58Ni, correlate with their GCE-dominated counterpart in silicon, 29Si/28Si. The measured GCE trends include the Solar System composition, showing that the Solar System is not a special case. However, as seen in silicon and titanium, many presolar SiC grains are more evolved for iron and nickel than the Solar System. This confirms prior findings and agrees with observations of large stellar samples that a simple age-metallicity relationship for GCE cannot explain the composition of the solar neighborhood.}, + abstract = {Aside from recording stellar nucleosynthesis, a few elements in + presolar grains can also provide insights into the galactic + chemical evolution (GCE) of nuclides. We have studied the carbon, + silicon, iron, and nickel isotopic compositions of presolar silicon + carbide (SiC) grains from asymptotic giant branch (AGB) stars to + better understand GCE. Since only the neutron-rich nuclides in + these grains have been heavily influenced by the parent star, the + neutron-poor nuclides serve as GCE proxies. Using CHILI, a new + resonance ionization mass spectrometry (RIMS) instrument, we + measured 74 presolar SiC grains for all iron and nickel isotopes. + With the CHARISMA instrument, 13 presolar SiC grains were analyzed + for iron isotopes. All grains were also measured by NanoSIMS for + their carbon and silicon isotopic compositions. A comparison of the + measured neutron-rich isotopes with models for AGB star + nucleosynthesis shows that our measurements are consistent with AGB + star predictions for low-mass stars between half-solar and solar + metallicity. Furthermore, our measurements give an indication on + the 22Ne({$\alpha$},n)25Mg reaction rate. In terms of GCE, we find + that the GCE-dominated iron and nickel isotope ratios, 54Fe/56Fe + and 60Ni/58Ni, correlate with their GCE-dominated counterpart in + silicon, 29Si/28Si. The measured GCE trends include the Solar + System composition, showing that the Solar System is not a special + case. However, as seen in silicon and titanium, many presolar SiC + grains are more evolved for iron and nickel than the Solar System. + This confirms prior findings and agrees with observations of large + stellar samples that a simple age-metallicity relationship for GCE + cannot explain the composition of the solar neighborhood.}, langid = {english}, - keywords = {-process,Galactic chemical evolution,Isotope anomalies,Presolar grains,Stellar nucleosynthesis} + keywords = {-process,Galactic chemical evolution,Isotope anomalies,Presolar + grains,Stellar nucleosynthesis}, } @article{SiC-2019-HOP-0, - title = {Isotopic Signatures of Supernova Nucleosynthesis in Presolar Silicon Carbide Grains of Type {{AB}} with Supersolar {\textsuperscript{14}}{{N}}/{\textsuperscript{15}}{{N}} Ratios}, - author = {Hoppe, Peter and Stancliffe, Richard J. and Pignatari, Marco and Amari, Sachiko}, - year = {2019}, + title = {Isotopic Signatures of Supernova Nucleosynthesis in Presolar Silicon + Carbide Grains of Type {{AB}} with Supersolar {$^{14}$} {{N}}/{$^{15}$ + }{{N}} Ratios}, + author = {Hoppe, Peter and Stancliffe, Richard J. and Pignatari, Marco and + Amari, Sachiko}, + year = 2019, month = dec, journal = {The Astrophysical Journal}, volume = {887}, @@ -1785,15 +4040,37 @@ @article{SiC-2019-HOP-0 issn = {0004-637X}, doi = {10.3847/1538-4357/ab521c}, urldate = {2023-02-15}, - abstract = {We report high-resolution C, N, Al, Si, and S isotope data of 38 presolar SiC grains of type AB. Seventeen of these grains are of subtype AB1 (14N/15N {$<$} 440 = solar) and 20 of subtype AB2 (14N/15N {$\geq$} 440), previously proposed to be mainly from supernovae (AB1) and J-type carbon stars (AB2), respectively. Our data are compatible with previously obtained isotope data of AB grains, except that 26Al/27Al ratios of AB1 grains span a narrower range. The data are compared with predictions from supernova models that consider H ingestion into the He shell during the pre-supernova phase. In these models a mixture of explosive H and He burning occurs at the bottom of the He shell during passage of the supernova shock, forming the so-called O/nova zone. Mixing matter from the O/nova zone with matter from the overlying He/C zone and the stellar envelope shows that the isotopic compositions and trends of both AB1 and AB2 grains can be matched within the model uncertainties. This demonstrates that supernovae should be considered as potential sources of AB2 grains, in addition to J-type carbon stars and born-again asymptotic giant branch stars, as previously proposed.}, - langid = {english} + abstract = {We report high-resolution C, N, Al, Si, and S isotope data of 38 + presolar SiC grains of type AB. Seventeen of these grains are of + subtype AB1 (14N/15N {$<$} 440 = solar) and 20 of subtype AB2 + (14N/15N {$\geq$} 440), previously proposed to be mainly from + supernovae (AB1) and J-type carbon stars (AB2), respectively. Our + data are compatible with previously obtained isotope data of AB + grains, except that 26Al/27Al ratios of AB1 grains span a narrower + range. The data are compared with predictions from supernova models + that consider H ingestion into the He shell during the + pre-supernova phase. In these models a mixture of explosive H and + He burning occurs at the bottom of the He shell during passage of + the supernova shock, forming the so-called O/nova zone. Mixing + matter from the O/nova zone with matter from the overlying He/C + zone and the stellar envelope shows that the isotopic compositions + and trends of both AB1 and AB2 grains can be matched within the + model uncertainties. This demonstrates that supernovae should be + considered as potential sources of AB2 grains, in addition to + J-type carbon stars and born-again asymptotic giant branch stars, + as previously proposed.}, + langid = {english}, } @article{SiC-2019-LIU-0, - title = {Presolar Silicon Carbide Grains of Types {{Y}} and {{Z}}: {{Their}} Molybdenum Isotopic Compositions and Stellar Origins}, + title = {Presolar Silicon Carbide Grains of Types {{Y}} and {{Z}}: {{Their}} + Molybdenum Isotopic Compositions and Stellar Origins}, shorttitle = {Presolar {{Silicon Carbide Grains}} of {{Types Y}} and {{Z}}}, - author = {Liu, Nan and Stephan, Thomas and Cristallo, Sergio and Gallino, Roberto and Boehnke, Patrick and Nittler, Larry R. and Alexander, C. M. O'D. and Davis, Andrew M. and Trappitsch, Reto and Pellin, Michael J. and Dillmann, Iris}, - year = {2019}, + author = {Liu, Nan and Stephan, Thomas and Cristallo, Sergio and Gallino, + Roberto and Boehnke, Patrick and Nittler, Larry R. and Alexander, C. + M. O'D. and Davis, Andrew M. and Trappitsch, Reto and Pellin, Michael + J. and Dillmann, Iris}, + year = 2019, month = aug, journal = {The Astrophysical Journal}, volume = {881}, @@ -1803,15 +4080,34 @@ @article{SiC-2019-LIU-0 issn = {0004-637X}, doi = {10.3847/1538-4357/ab2d27}, urldate = {2023-02-15}, - abstract = {We report Mo isotopic compositions of 37 presolar SiC grains of types Y (19) and Z (18), rare types commonly argued to have formed in lower-than-solar metallicity asymptotic giant branch (AGB) stars. Direct comparison of the Y and Z grain data with data for mainstream grains from AGB stars of close-to-solar metallicity demonstrates that the three types of grains have indistinguishable Mo isotopic compositions. We show that the Mo isotope data can be used to constrain the maximum stellar temperatures (TMAX) during thermal pulses in AGB stars. Comparison of FRUITY Torino AGB nucleosynthesis model calculations with the grain data for Mo isotopes points to an origin from low-mass ({$\sim$}1.5--3 M{$\odot$}) rather than intermediate-mass ({$>$}3--{$\sim$}9 M{$\odot$}) AGB stars. Because of the low efficiency of 22Ne({$\alpha$}, n)25Mg at the low TMAX values attained in low-mass AGB stars, model calculations cannot explain the large 30Si excesses of Z grains as arising from neutron capture, so these excesses remain a puzzle at the moment.}, - langid = {english} + abstract = {We report Mo isotopic compositions of 37 presolar SiC grains of + types Y (19) and Z (18), rare types commonly argued to have formed + in lower-than-solar metallicity asymptotic giant branch (AGB) + stars. Direct comparison of the Y and Z grain data with data for + mainstream grains from AGB stars of close-to-solar metallicity + demonstrates that the three types of grains have indistinguishable + Mo isotopic compositions. We show that the Mo isotope data can be + used to constrain the maximum stellar temperatures (TMAX) during + thermal pulses in AGB stars. Comparison of FRUITY Torino AGB + nucleosynthesis model calculations with the grain data for Mo + isotopes points to an origin from low-mass ({$\sim$}1.5--3 M{$\odot + $}) rather than intermediate-mass ({$>$}3--{$\sim$}9 M{$\odot$}) + AGB stars. Because of the low efficiency of 22Ne({$\alpha$}, n)25Mg + at the low TMAX values attained in low-mass AGB stars, model + calculations cannot explain the large 30Si excesses of Z grains as + arising from neutron capture, so these excesses remain a puzzle at + the moment.}, + langid = {english}, } @article{SiC-2019-STE-0, - title = {Molybdenum Isotopes in Presolar Silicon Carbide Grains: {{Details}} of {\emph{s}}-Process Nucleosynthesis in Parent Stars and Implications for {\emph{r}}- and {\emph{p}}-Processes}, + title = {Molybdenum Isotopes in Presolar Silicon Carbide Grains: {{Details}} + of {\emph{s}}-Process Nucleosynthesis in Parent Stars and Implications + for {\emph{r}}- and {\emph{p}}-Processes}, shorttitle = {Molybdenum {{Isotopes}} in {{Presolar Silicon Carbide Grains}}}, - author = {Stephan, Thomas and Trappitsch, Reto and Hoppe, Peter and Davis, Andrew M. and Pellin, Michael J. and Pardo, Olivia S.}, - year = {2019}, + author = {Stephan, Thomas and Trappitsch, Reto and Hoppe, Peter and Davis, + Andrew M. and Pellin, Michael J. and Pardo, Olivia S.}, + year = 2019, month = may, journal = {The Astrophysical Journal}, volume = {877}, @@ -1821,15 +4117,46 @@ @article{SiC-2019-STE-0 issn = {0004-637X}, doi = {10.3847/1538-4357/ab1c60}, urldate = {2023-02-15}, - abstract = {We have analyzed molybdenum isotopes, together with strontium and barium isotopes, in 18 presolar silicon carbide grains using the Chicago Instrument for Laser Ionization (CHILI), a resonance ionization mass spectrometer. All observed isotope ratios can be explained by mixtures of pure s-process matter with isotopically solar material. Grain residues were subsequently analyzed for carbon, nitrogen, silicon, and sulfur isotopes, as well as a subset for 26Al--26Mg systematics using the NanoSIMS. These analyses showed that all but one grain are mainstream grains, most probably coming from low-mass asymptotic giant branch (AGB) stars. One grain is of the AB type, for which the origin is still a matter of debate. The high precision of molybdenum isotope measurements with CHILI provides the best estimate to date for s-process molybdenum made in low-mass AGB stars. The average molybdenum isotopic abundances produced by the s-process found in the analyzed mainstream SiC grains are 0\% 92Mo, 0.73\% 94Mo, 13.30\% 95Mo, 36.34\% 96Mo, 9.78\% 97Mo, 39.42\% 98Mo, and 0.43\% 100Mo. Solar molybdenum can be explained as a combination of 45.9\% s-process, 30.6\% r-process, and 23.5\% p-process contributions. Furthermore, the observed variability in the individual grain data provides insights into the variability of conditions (neutron density, temperature, and timescale) during s-process nucleosynthesis in the grains' parent stars, as they have subtle effects on specific molybdenum isotope ratios. Finally, the results suggest that the ratio between p- and r-process molybdenum in presolar SiC from many different types of parent stars is Mop/Mor = 0.767, the value inferred for the solar system and consistent with what has been found in bulk samples and leachates of primitive meteorites.}, - langid = {english} + abstract = {We have analyzed molybdenum isotopes, together with strontium and + barium isotopes, in 18 presolar silicon carbide grains using the + Chicago Instrument for Laser Ionization (CHILI), a resonance + ionization mass spectrometer. All observed isotope ratios can be + explained by mixtures of pure s-process matter with isotopically + solar material. Grain residues were subsequently analyzed for + carbon, nitrogen, silicon, and sulfur isotopes, as well as a subset + for 26Al--26Mg systematics using the NanoSIMS. These analyses + showed that all but one grain are mainstream grains, most probably + coming from low-mass asymptotic giant branch (AGB) stars. One grain + is of the AB type, for which the origin is still a matter of + debate. The high precision of molybdenum isotope measurements with + CHILI provides the best estimate to date for s-process molybdenum + made in low-mass AGB stars. The average molybdenum isotopic + abundances produced by the s-process found in the analyzed + mainstream SiC grains are 0\% 92Mo, 0.73\% 94Mo, 13.30\% 95Mo, + 36.34\% 96Mo, 9.78\% 97Mo, 39.42\% 98Mo, and 0.43\% 100Mo. Solar + molybdenum can be explained as a combination of 45.9\% s-process, + 30.6\% r-process, and 23.5\% p-process contributions. Furthermore, + the observed variability in the individual grain data provides + insights into the variability of conditions (neutron density, + temperature, and timescale) during s-process nucleosynthesis in the + grains' parent stars, as they have subtle effects on specific + molybdenum isotope ratios. Finally, the results suggest that the + ratio between p- and r-process molybdenum in presolar SiC from many + different types of parent stars is Mop/Mor = 0.767, the value + inferred for the solar system and consistent with what has been + found in bulk samples and leachates of primitive meteorites.}, + langid = {english}, } @article{SiC-2020-LEI-0, - title = {The Presolar Grain Inventory of Fine-grained Chondrule Rims in the {{Mighei}}-type ({{CM}}) Chondrites}, - shorttitle = {The Presolar Grain Inventory of Fine-grained Chondrule Rims in the {{Mighei}}-type (}, - author = {Leitner, Jan and Metzler, Knut and Vollmer, Christian and Floss, Christine and Haenecour, Pierre and Kodol{\'a}nyi, J{\'a}nos and Harries, Dennis and Hoppe, Peter}, - year = {2020}, + title = {The Presolar Grain Inventory of Fine-Grained Chondrule Rims in the {{ + Mighei-type}} ({{CM}}) Chondrites}, + shorttitle = {The Presolar Grain Inventory of Fine-Grained Chondrule Rims in + the {{Mighei-type}} (}, + author = {Leitner, Jan and Metzler, Knut and Vollmer, Christian and Floss, + Christine and Haenecour, Pierre and Kodol{\'a}nyi, J{\'a}nos and + Harries, Dennis and Hoppe, Peter}, + year = 2020, month = jun, journal = {Meteoritics \& Planetary Science}, volume = {55}, @@ -1838,14 +4165,44 @@ @article{SiC-2020-LEI-0 issn = {1086-9379, 1945-5100}, doi = {10.1111/maps.13412}, urldate = {2025-03-24}, - abstract = {Abstract We investigated the inventory of presolar silicate, oxide, and silicon carbide (SiC) grains of fine-grained chondrule rims in six Mighei-type ( CM ) carbonaceous chondrites (Banten, Jbilet Winselwan, Maribo, Murchison, Murray and Yamato 791198), and the CM -related carbonaceous chondrite Sutter's Mill. Sixteen O-anomalous grains (nine silicates, six oxides) were detected, corresponding to a combined matrix-normalized abundance of {\textasciitilde}18 ppm, together with 21 presolar SiC grains ({\textasciitilde}42~ppm). Twelve of the O-rich grains are enriched in 17 O, and could originate from low-mass asymptotic giant branch stars. One grain is enriched in 17 O and significantly depleted in 18 O, indicative of additional cool bottom processing or hot bottom burning in its stellar parent, and three grains are of likely core-collapse supernova origin showing enhanced 18 O/ 16 O ratios relative to the solar system ratio. We find a presolar silicate/oxide ratio of 1.5, significantly lower than the ratios typically observed for chondritic meteorites. This may indicate a higher degree of aqueous alteration in the studied meteorites, or hint at a heterogeneous distribution of presolar silicates and oxides in the solar nebula. Nevertheless, the low O-anomalous grain abundance is consistent with aqueous alteration occurring in the protosolar nebula and/or on the respective parent bodies. Six O-rich presolar grains were studied by Auger Electron Spectroscopy, revealing two Fe-rich silicates, one forsterite-like Mg-rich silicate, two Al-oxides with spinel-like compositions, and one Fe-(Mg-)oxide. Scanning electron and transmission electron microscopic investigation of a relatively large silicate grain (490~nm~{\texttimes}~735~nm) revealed that it was crystalline {\aa}kermanite (Ca 2 Mg[Si 2 O 7 ]) or a an {\aa}kermanite-diopside (MgCaSi 2 O 6 ) intergrowth.}, - langid = {english} + abstract = {Abstract We investigated the inventory of presolar silicate, oxide + , and silicon carbide (SiC) grains of fine-grained chondrule rims + in six Mighei-type ( CM ) carbonaceous chondrites (Banten, Jbilet + Winselwan, Maribo, Murchison, Murray and Yamato 791198), and the CM + -related carbonaceous chondrite Sutter's Mill. Sixteen O-anomalous + grains (nine silicates, six oxides) were detected, corresponding to + a combined matrix-normalized abundance of \textasciitilde 18 ppm, + together with 21 presolar SiC grains (\textasciitilde 42 ppm). + Twelve of the O-rich grains are enriched in 17 O, and could + originate from low-mass asymptotic giant branch stars. One grain is + enriched in 17 O and significantly depleted in 18 O, indicative of + additional cool bottom processing or hot bottom burning in its + stellar parent, and three grains are of likely core-collapse + supernova origin showing enhanced 18 O/ 16 O ratios relative to the + solar system ratio. We find a presolar silicate/oxide ratio of 1.5, + significantly lower than the ratios typically observed for + chondritic meteorites. This may indicate a higher degree of aqueous + alteration in the studied meteorites, or hint at a heterogeneous + distribution of presolar silicates and oxides in the solar nebula. + Nevertheless, the low O-anomalous grain abundance is consistent + with aqueous alteration occurring in the protosolar nebula and/or + on the respective parent bodies. Six O-rich presolar grains were + studied by Auger Electron Spectroscopy, revealing two Fe-rich + silicates, one forsterite-like Mg-rich silicate, two Al-oxides with + spinel-like compositions, and one Fe-(Mg-)oxide. Scanning electron + and transmission electron microscopic investigation of a relatively + large silicate grain (490 nm \texttimes{} 735 nm) revealed that it + was crystalline \aa kermanite (Ca 2 Mg[Si 2 O 7 ]) or a an \aa{} + kermanite-diopside (MgCaSi 2 O 6 ) intergrowth.}, + langid = {english}, } @article{SiC-2020-NIT-0, - title = {Presolar Grains in Primitive Ungrouped Carbonaceous Chondrite {{Northwest Africa}} 5958}, - author = {Nittler, Larry R. and Stroud, Rhonda M. and Alexander, C. M. O'D. and Howell, Kaitlin}, - year = {2020}, + title = {Presolar Grains in Primitive Ungrouped Carbonaceous Chondrite {{ + Northwest Africa}} 5958}, + author = {Nittler, Larry R. and Stroud, Rhonda M. and Alexander, C. M. O'D. + and Howell, Kaitlin}, + year = 2020, journal = {Meteoritics \& Planetary Science}, volume = {55}, number = {6}, @@ -1853,15 +4210,42 @@ @article{SiC-2020-NIT-0 issn = {1945-5100}, doi = {10.1111/maps.13397}, urldate = {2023-02-15}, - abstract = {We report a correlated NanoSIMS-transmission electron microscopy study of the ungrouped carbonaceous chondrite Northwest Africa (NWA) 5958. We identified 10 presolar SiC grains, 2 likely presolar graphite grains, and 20 presolar silicate and/or oxide grains in NWA 5958. We suggest a slight modification of the commonly used classification system for presolar oxides and silicates that better reflects the grains' likely stellar origins. The matrix-normalized presolar SiC abundance in NWA 5958 is ppm (2{$\sigma$}) similar to that seen in many classes of unmetamorphosed chondrites. In contrast, the matrix-normalized abundance of presolar O-rich phases (silicates and oxides) is ppm (2{$\sigma$}), much lower than seen in interplanetary dust particles and the least-altered CR, CO, and ungrouped C chondrites, but close to that reported for CM chondrites. NanoSIMS mapping also revealed an unusual 13C-enriched ({$\delta$}13C{$\approx$}100--200‰) carbonaceous rim surrounding a 1.4 {$\mu$}m diameter phyllosilicate grain. Transmission electron microscopy (TEM) analysis of two presolar grains with a likely origin in asymptotic giant branch stars identified one as enstatite and one as Al-Mg spinel with minor Cr. The enstatite grain amorphized rapidly under the electron beam, suggesting partial hydration. TEM data of NWA 5958 matrix confirm that it has experienced aqueous alteration and support the suggestion of Jacquet et al. (34) that this meteorite has affinities to CM2 chondrites.}, - langid = {english} + abstract = {We report a correlated NanoSIMS-transmission electron microscopy + study of the ungrouped carbonaceous chondrite Northwest Africa + (NWA) 5958. We identified 10 presolar SiC grains, 2 likely presolar + graphite grains, and 20 presolar silicate and/or oxide grains in + NWA 5958. We suggest a slight modification of the commonly used + classification system for presolar oxides and silicates that better + reflects the grains' likely stellar origins. The matrix-normalized + presolar SiC abundance in NWA 5958 is ppm (2{$\sigma$}) similar to + that seen in many classes of unmetamorphosed chondrites. In + contrast, the matrix-normalized abundance of presolar O-rich phases + (silicates and oxides) is ppm (2{$\sigma$}), much lower than seen + in interplanetary dust particles and the least-altered CR, CO, and + ungrouped C chondrites, but close to that reported for CM + chondrites. NanoSIMS mapping also revealed an unusual 13C-enriched + ({$\delta$}13C{$\approx$}100--200‰) carbonaceous rim surrounding a + 1.4 {$\mu$}m diameter phyllosilicate grain. Transmission electron + microscopy (TEM) analysis of two presolar grains with a likely + origin in asymptotic giant branch stars identified one as enstatite + and one as Al-Mg spinel with minor Cr. The enstatite grain + amorphized rapidly under the electron beam, suggesting partial + hydration. TEM data of NWA 5958 matrix confirm that it has + experienced aqueous alteration and support the suggestion of + Jacquet et al. (34) that this meteorite has affinities to CM2 + chondrites.}, + langid = {english}, } @article{SiC-2021-LIU-0, - title = {New Multielement Isotopic Compositions of Presolar {{SiC}} Grains: {{Implications}} for Their Stellar Origins}, - shorttitle = {New {{Multielement Isotopic Compositions}} of {{Presolar SiC Grains}}}, - author = {Liu, Nan and Barosch, Jens and Nittler, Larry R. and Alexander, C. M. O'D. and Wang, Jianhua and Cristallo, Sergio and Busso, Maurizio and Palmerini, Sara}, - year = {2021}, + title = {New Multielement Isotopic Compositions of Presolar {{SiC}} Grains: {{ + Implications}} for Their Stellar Origins}, + shorttitle = {New {{Multielement Isotopic Compositions}} of {{Presolar SiC + Grains}}}, + author = {Liu, Nan and Barosch, Jens and Nittler, Larry R. and Alexander, C. + M. O'D. and Wang, Jianhua and Cristallo, Sergio and Busso, Maurizio + and Palmerini, Sara}, + year = 2021, month = oct, journal = {The Astrophysical Journal Letters}, volume = {920}, @@ -1871,14 +4255,36 @@ @article{SiC-2021-LIU-0 issn = {2041-8205}, doi = {10.3847/2041-8213/ac260b}, urldate = {2023-02-15}, - abstract = {We report NanoSIMS Si and Mg--Al isotopic data (and C, N, and Ti isotopic data, when available) for 85 submicron- to micron-sized presolar SiC grains from the CM2 Murchison meteorite, including 60 mainstream (MS), 8 AB1, 8 X, 7 AB2, and 2 Y grains. The MS and Y grain data demonstrate that (1) C and N contamination mainly appears as surface contamination, and sufficient presputtering is needed to expose a clean grain surface for obtaining intrinsic C and N signals, and (2) Mg and Al contamination appears as adjacent grains and rims, and high-resolution imaging and the choice of small regions of interest during data reduction together are effective in suppressing the contamination. Our results strongly indicate that previous studies of presolar SiC grains could have sampled differing degrees of contamination for C, N, Mg, and Al. Compared to the literature data, our new MS and Y grains are in better agreement with carbon star observations for both the C and N isotopic ratios. By comparing our new, tighter distributions of 12C/13C, 14N/15N, and initial 26Al/27Al ratios for MS and Y grains with FRUITY low-mass asymptotic giant branch (AGB) stellar models, we provide more stringent constraints on the occurrence of cool bottom processing and the production of 26Al in N-type carbon stars, which are classical AGB stars.}, - langid = {english} + abstract = {We report NanoSIMS Si and Mg--Al isotopic data (and C, N, and Ti + isotopic data, when available) for 85 submicron- to micron-sized + presolar SiC grains from the CM2 Murchison meteorite, including 60 + mainstream (MS), 8 AB1, 8 X, 7 AB2, and 2 Y grains. The MS and Y + grain data demonstrate that (1) C and N contamination mainly + appears as surface contamination, and sufficient presputtering is + needed to expose a clean grain surface for obtaining intrinsic C + and N signals, and (2) Mg and Al contamination appears as adjacent + grains and rims, and high-resolution imaging and the choice of + small regions of interest during data reduction together are + effective in suppressing the contamination. Our results strongly + indicate that previous studies of presolar SiC grains could have + sampled differing degrees of contamination for C, N, Mg, and Al. + Compared to the literature data, our new MS and Y grains are in + better agreement with carbon star observations for both the C and N + isotopic ratios. By comparing our new, tighter distributions of + 12C/13C, 14N/15N, and initial 26Al/27Al ratios for MS and Y grains + with FRUITY low-mass asymptotic giant branch (AGB) stellar models, + we provide more stringent constraints on the occurrence of cool + bottom processing and the production of 26Al in N-type carbon stars + , which are classical AGB stars.}, + langid = {english}, } @article{SiC-2021-NIT-0, - title = {Presolar Stardust in Highly Pristine {{CM}} Chondrites {{Asuka}} 12169 and {{Asuka}} 12236}, - author = {Nittler, Larry R. and Alexander, C. M. O'D. and Patzer, Andrea and {Verdier-Paoletti}, Maximilien J.}, - year = {2021}, + title = {Presolar Stardust in Highly Pristine {{CM}} Chondrites {{Asuka}} + 12169 and {{Asuka}} 12236}, + author = {Nittler, Larry R. and Alexander, C. M. O'D. and Patzer, Andrea and { + Verdier-Paoletti}, Maximilien J.}, + year = 2021, journal = {Meteoritics \& Planetary Science}, volume = {56}, number = {2}, @@ -1886,14 +4292,77 @@ @article{SiC-2021-NIT-0 issn = {1945-5100}, doi = {10.1111/maps.13618}, urldate = {2023-02-15}, - abstract = {We report a NanoSIMS search for presolar grains in the CM chondrites Asuka (A) 12169 and A12236. We found 90 presolar O-rich grains and 25 SiC grains in A12169, giving matrix-normalized abundances of 275 (+55/-50, 1{$\sigma$}) ppm or, excluding an unusually large grain, 236 (+37/-34) ppm for O-rich grains and 62 (+15/-12) ppm for SiC grains. For A12236, 18 presolar silicates and 6 SiCs indicate abundances of 58 (+18/-12) and 20 (+12/-8) ppm, respectively. The SiC abundances are in the typical range of primitive chondrites. The abundance of presolar O-rich grains in A12169 is essentially identical to that in CO3.0 Dominion Range 08006, higher than in any other chondrites, while in A12236, it is higher than found in other CMs. These abundances provide further strong support that A12169 and A12236 are the least-altered CMs as indicated by petrographic investigations. The similar abundances, isotopic distributions, silicate/oxide ratios, and grain sizes of the presolar O-rich grains found here to those of presolar grains in highly primitive CO, CR, and ungrouped carbonaceous chondrites (CCs) indicate that the CM parent body(ies) accreted a similar population of presolar oxides and silicates in their matrices to those accreted by the parent bodies of the other CC groups. The lower abundances and larger grain sizes seen in some other CMs are thus most likely a result of parent-body alteration and not heterogeneity in nebular precursors. Presolar silicates are unlikely to be present in high abundances in returned samples from asteroids Ryugu and Bennu since remote-sensing data indicate that they have experienced substantial aqueous alteration.}, - langid = {english} + abstract = {We report a NanoSIMS search for presolar grains in the CM + chondrites Asuka (A) 12169 and A12236. We found 90 presolar O-rich + grains and 25 SiC grains in A12169, giving matrix-normalized + abundances of 275 (+55/-50, 1{$\sigma$}) ppm or, excluding an + unusually large grain, 236 (+37/-34) ppm for O-rich grains and 62 + (+15/-12) ppm for SiC grains. For A12236, 18 presolar silicates and + 6 SiCs indicate abundances of 58 (+18/-12) and 20 (+12/-8) ppm, + respectively. The SiC abundances are in the typical range of + primitive chondrites. The abundance of presolar O-rich grains in + A12169 is essentially identical to that in CO3.0 Dominion Range + 08006, higher than in any other chondrites, while in A12236, it is + higher than found in other CMs. These abundances provide further + strong support that A12169 and A12236 are the least-altered CMs as + indicated by petrographic investigations. The similar abundances, + isotopic distributions, silicate/oxide ratios, and grain sizes of + the presolar O-rich grains found here to those of presolar grains + in highly primitive CO, CR, and ungrouped carbonaceous chondrites + (CCs) indicate that the CM parent body(ies) accreted a similar + population of presolar oxides and silicates in their matrices to + those accreted by the parent bodies of the other CC groups. The + lower abundances and larger grain sizes seen in some other CMs are + thus most likely a result of parent-body alteration and not + heterogeneity in nebular precursors. Presolar silicates are + unlikely to be present in high abundances in returned samples from + asteroids Ryugu and Bennu since remote-sensing data indicate that + they have experienced substantial aqueous alteration.}, + langid = {english}, } @article{SiC-2022-BAR-0, title = {Presolar Stardust in Asteroid {{Ryugu}}}, - author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and Alexander, C. M. O'D. and Gregorio, Bradley T. De and Engrand, C{\'e}cile and Kebukawa, Yoko and Nagashima, Kazuhide and Stroud, Rhonda M. and Yabuta, Hikaru and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and Amari, Sachiko and Amelin, Yuri and Bajo, Ken-ichi and Bejach, Laure and Bizzarro, Martin and Bonal, Lydie and Bouvier, Audrey and Carlson, Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Cody, George D. and Dartois, Emmanuel and Dauphas, Nicolas and Davis, Andrew M. and Dazzi, Alexandre and {Deniset-Besseau}, Ariane and Rocco, Tommaso Di and Duprat, Jean and Fujiya, Wataru and Fukai, Ryota and Gautam, Ikshu and Haba, Makiko K. and Hashiguchi, Minako and Hibiya, Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter and Huss, Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and Ireland, Trevor R. and Ishikawa, Akira and Ito, Motoo and Itoh, Shoichi and Kamide, Kanami and Kawasaki, Noriyuki and Kilcoyne, A. L. David and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten and Komatani, Shintaro and Komatsu, Mutsumi and Krot, Alexander N. and Liu, Ming-Chang and Martins, Zita and Masuda, Yuki and Mathurin, J{\'e}r{\'e}mie and McKeegan, Kevin D. and Montagnac, Gilles and Morita, Mayu and Mostefaoui, Smail and Motomura, Kazuko and Moynier, Fr{\'e}d{\'e}ric and Nakai, Izumi and Nguyen, Ann N. and Ohigashi, Takuji and Okumura, Taiga and Onose, Morihiko and Pack, Andreas and Park, Changkun and Piani, Laurette and Qin, Liping and Quirico, Eric and Remusat, Laurent and Russell, Sara S. and Sakamoto, Naoya and Sandford, Scott A. and Sch{\"o}nb{\"a}chler, Maria and Shigenaka, Miho and Suga, Hiroki and Tafla, Lauren and Takahashi, Yoshio and Takeichi, Yasuo and Tamenori, Yusuke and Tang, Haolan and Terada, Kentaro and Terada, Yasuko and Usui, Tomohiro and {Verdier-Paoletti}, Maximilien and Wada, Sohei and Wadhwa, Meenakshi and Wakabayashi, Daisuke and Walker, Richard J. and Yamashita, Katsuyuki and Yamashita, Shohei and Yin, Qing-Zhu and Yokoyama, Tetsuya and Yoneda, Shigekazu and Young, Edward D. and Yui, Hiroharu and Zhang, Ai-Cheng and Abe, Masanao and Miyazaki, Akiko and Nakato, Aiko and Nakazawa, Satoru and Nishimura, Masahiro and Okada, Tatsuaki and Saiki, Takanao and Tanaka, Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, Sei-ichiro and Yada, Toru and Yogata, Kasumi and Yoshikawa, Makoto and Nakamura, Tomoki and Naraoka, Hiroshi and Noguchi, Takaaki and Okazaki, Ryuji and Sakamoto, Kanako and Tachibana, Shogo and Yurimoto, Hisayoshi}, - year = {2022}, + author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and Alexander, + C. M. O'D. and Gregorio, Bradley T. De and Engrand, C{\'e}cile and + Kebukawa, Yoko and Nagashima, Kazuhide and Stroud, Rhonda M. and + Yabuta, Hikaru and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and + Amari, Sachiko and Amelin, Yuri and Bajo, Ken-ichi and Bejach, Laure + and Bizzarro, Martin and Bonal, Lydie and Bouvier, Audrey and Carlson + , Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Cody, + George D. and Dartois, Emmanuel and Dauphas, Nicolas and Davis, + Andrew M. and Dazzi, Alexandre and {Deniset-Besseau}, Ariane and + Rocco, Tommaso Di and Duprat, Jean and Fujiya, Wataru and Fukai, + Ryota and Gautam, Ikshu and Haba, Makiko K. and Hashiguchi, Minako + and Hibiya, Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, + Peter and Huss, Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and + Ireland, Trevor R. and Ishikawa, Akira and Ito, Motoo and Itoh, + Shoichi and Kamide, Kanami and Kawasaki, Noriyuki and Kilcoyne, A. L. + David and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten + and Komatani, Shintaro and Komatsu, Mutsumi and Krot, Alexander N. + and Liu, Ming-Chang and Martins, Zita and Masuda, Yuki and Mathurin, + J{\'e}r{\'e}mie and McKeegan, Kevin D. and Montagnac, Gilles and + Morita, Mayu and Mostefaoui, Smail and Motomura, Kazuko and Moynier, + Fr{\'e}d{\'e}ric and Nakai, Izumi and Nguyen, Ann N. and Ohigashi, + Takuji and Okumura, Taiga and Onose, Morihiko and Pack, Andreas and + Park, Changkun and Piani, Laurette and Qin, Liping and Quirico, Eric + and Remusat, Laurent and Russell, Sara S. and Sakamoto, Naoya and + Sandford, Scott A. and Sch{\"o}nb{\"a}chler, Maria and Shigenaka, + Miho and Suga, Hiroki and Tafla, Lauren and Takahashi, Yoshio and + Takeichi, Yasuo and Tamenori, Yusuke and Tang, Haolan and Terada, + Kentaro and Terada, Yasuko and Usui, Tomohiro and {Verdier-Paoletti}, + Maximilien and Wada, Sohei and Wadhwa, Meenakshi and Wakabayashi, + Daisuke and Walker, Richard J. and Yamashita, Katsuyuki and Yamashita + , Shohei and Yin, Qing-Zhu and Yokoyama, Tetsuya and Yoneda, + Shigekazu and Young, Edward D. and Yui, Hiroharu and Zhang, Ai-Cheng + and Abe, Masanao and Miyazaki, Akiko and Nakato, Aiko and Nakazawa, + Satoru and Nishimura, Masahiro and Okada, Tatsuaki and Saiki, Takanao + and Tanaka, Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, + Sei-ichiro and Yada, Toru and Yogata, Kasumi and Yoshikawa, Makoto + and Nakamura, Tomoki and Naraoka, Hiroshi and Noguchi, Takaaki and + Okazaki, Ryuji and Sakamoto, Kanako and Tachibana, Shogo and Yurimoto + , Hisayoshi}, + year = 2022, month = aug, journal = {The Astrophysical Journal Letters}, volume = {935}, @@ -1903,14 +4372,41 @@ @article{SiC-2022-BAR-0 issn = {2041-8205}, doi = {10.3847/2041-8213/ac83bd}, urldate = {2023-02-15}, - abstract = {We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are ppm for O-anomalous grains, ppm for SiC grains, and ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of 15 SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: ppm SiC and ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu--CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material.}, - langid = {english} + abstract = {We have conducted a NanoSIMS-based search for presolar material in + samples recently returned from C-type asteroid Ryugu as part of + JAXA's Hayabusa2 mission. We report the detection of all major + presolar grain types with O- and C-anomalous isotopic compositions + typically identified in carbonaceous chondrite meteorites: 1 + silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase + , 38 SiC, and 16 carbonaceous grains. At least two of the + carbonaceous grains are presolar graphites, whereas several grains + with moderate C isotopic anomalies are probably organics. The + presolar silicate was located in a clast with a less altered + lithology than the typical extensively aqueously altered Ryugu + matrix. The matrix-normalized presolar grain abundances in Ryugu + are ppm for O-anomalous grains, ppm for SiC grains, and ppm for + carbonaceous grains. Ryugu is isotopically and petrologically + similar to carbonaceous Ivuna-type (CI) chondrites. To compare the + in situ presolar grain abundances of Ryugu with CI chondrites, we + also mapped Ivuna and Orgueil samples and found a total of 15 SiC + grains and 6 carbonaceous grains. No O-anomalous grains were + detected. The matrix-normalized presolar grain abundances in the CI + chondrites are similar to those in Ryugu: ppm SiC and ppm + carbonaceous grains. Thus, our results provide further evidence in + support of the Ryugu--CI connection. They also reveal intriguing + hints of small-scale heterogeneities in the Ryugu samples, such as + locally distinct degrees of alteration that allowed the + preservation of delicate presolar material.}, + langid = {english}, } @article{SiC-2022-BAR-1, - title = {Presolar {{O-}} and {{C-anomalous}} Grains in Unequilibrated Ordinary Chondrite Matrices}, - author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and Dobric{\u a}, Elena and Brearley, Adrian J. and Hezel, Dominik C. and Alexander, C. M. O'D.}, - year = {2022}, + title = {Presolar {{O-}} and {{C-anomalous}} Grains in Unequilibrated Ordinary + Chondrite Matrices}, + author = {Barosch, Jens and Nittler, Larry R. and Wang, Jianhua and Dobric{\u + a}, Elena and Brearley, Adrian J. and Hezel, Dominik C. and Alexander + , C. M. O'D.}, + year = 2022, month = oct, journal = {Geochimica et Cosmochimica Acta}, volume = {335}, @@ -1918,16 +4414,51 @@ @article{SiC-2022-BAR-1 issn = {0016-7037}, doi = {10.1016/j.gca.2022.08.027}, urldate = {2023-02-15}, - abstract = {Presolar grains are trace components in chondrite matrices. Their abundances and compositions have been systematically studied in carbonaceous chondrites but rarely in situ in other major chondrite classes. We have conducted a NanoSIMS isotopic search for presolar grains with O- and C-anomalous isotopic compositions in the matrices of the unequilibrated ordinary chondrites Semarkona (LL3.00), Meteorite Hills 00526 (L/LL3.05), and Northwest Africa 8276 (L3.00). The matrices of even the most primitive ordinary chondrites have been aqueously altered and/or thermally metamorphosed, destroying their presolar grain populations to varying extents. In addition to randomly placed isotope maps, we specifically targeted recently reported, relatively pristine Semarkona matrix areas to better explore the original inventory of presolar grains in this meteorite. In all samples, we found a total of 122 O-anomalous grains (silicates~+~oxides), 79 SiC grains, and 22 C-anomalous carbonaceous grains (organics, graphites). Average matrix-normalized abundances with 1{$\sigma$} uncertainties are 151-46+50 ppm O-anomalous grains, 53-12+14 ppm SiC grains and 56-14+19 ppm carbonaceous grains in Semarkona, 55-10+11 ppm (O-anom.), 22-4+5 ppm (SiC) and 3-1+2 ppm (carb.) in MET 00526 and 12-3+6 ppm (O-anom.), 15-5+7 ppm (SiC) and 1-1+3 ppm (carb.) in NWA 8276. In relatively pristine ordinary chondrites and in primitive carbonaceous and C-ungrouped chondrites, the O and C isotopic composition of presolar grains and their matrix-normalized abundances are similar, despite the likely differences in chondrite-formation time and nebular location. These results suggest a relatively homogenous distribution of presolar dust across major chondrite-forming reservoirs in the solar nebula. Secondary asteroidal processes are mainly responsible for differences in presolar grain abundances between and within chondrites, highlighting the need to identify and target the most pristine chondrite matrices for such studies.}, + abstract = {Presolar grains are trace components in chondrite matrices. Their + abundances and compositions have been systematically studied in + carbonaceous chondrites but rarely in situ in other major chondrite + classes. We have conducted a NanoSIMS isotopic search for presolar + grains with O- and C-anomalous isotopic compositions in the + matrices of the unequilibrated ordinary chondrites Semarkona + (LL3.00), Meteorite Hills 00526 (L/LL3.05), and Northwest Africa + 8276 (L3.00). The matrices of even the most primitive ordinary + chondrites have been aqueously altered and/or thermally + metamorphosed, destroying their presolar grain populations to + varying extents. In addition to randomly placed isotope maps, we + specifically targeted recently reported, relatively pristine + Semarkona matrix areas to better explore the original inventory of + presolar grains in this meteorite. In all samples, we found a total + of 122 O-anomalous grains (silicates + oxides), 79 SiC grains, and + 22 C-anomalous carbonaceous grains (organics, graphites). Average + matrix-normalized abundances with 1{$\sigma$} uncertainties are + 151-46+50 ppm O-anomalous grains, 53-12+14 ppm SiC grains and + 56-14+19 ppm carbonaceous grains in Semarkona, 55-10+11 ppm + (O-anom.), 22-4+5 ppm (SiC) and 3-1+2 ppm (carb.) in MET 00526 and + 12-3+6 ppm (O-anom.), 15-5+7 ppm (SiC) and 1-1+3 ppm (carb.) in NWA + 8276. In relatively pristine ordinary chondrites and in primitive + carbonaceous and C-ungrouped chondrites, the O and C isotopic + composition of presolar grains and their matrix-normalized + abundances are similar, despite the likely differences in + chondrite-formation time and nebular location. These results + suggest a relatively homogenous distribution of presolar dust + across major chondrite-forming reservoirs in the solar nebula. + Secondary asteroidal processes are mainly responsible for + differences in presolar grain abundances between and within + chondrites, highlighting the need to identify and target the most + pristine chondrite matrices for such studies.}, langid = {english}, - keywords = {Isotope dilution correction,NanoSIMS,Ordinary chondrites,Presolar grains} + keywords = {Isotope dilution correction,NanoSIMS,Ordinary chondrites,Presolar + grains}, } @article{SiC-2022-LIU-0, - title = {Presolar Silicon Carbide Grains of Types {{Y}} and {{Z}}: Their Strontium and Barium Isotopic Compositions and Stellar Origins}, + title = {Presolar Silicon Carbide Grains of Types {{Y}} and {{Z}}: {{Their}} + Strontium and Barium Isotopic Compositions and Stellar Origins}, shorttitle = {Presolar Silicon Carbide Grains of Types {{Y}} and {{Z}}}, - author = {Liu, Nan and Stephan, Thomas and Cristallo, Sergio and Vescovi, Diego and Gallino, Roberto and Nittler, Larry R. and Alexander, C. M. O'D. and Davis, Andrew M.}, - year = {2022}, + author = {Liu, Nan and Stephan, Thomas and Cristallo, Sergio and Vescovi, + Diego and Gallino, Roberto and Nittler, Larry R. and Alexander, C. M. + O'D. and Davis, Andrew M.}, + year = 2022, month = nov, journal = {The European Physical Journal A}, volume = {58}, @@ -1936,14 +4467,29 @@ @article{SiC-2022-LIU-0 issn = {1434-601X}, doi = {10.1140/epja/s10050-022-00838-z}, urldate = {2023-02-15}, - abstract = {We report the Sr and Ba isotopic compositions of 18 presolar SiC grains of types Y (11) and Z (7), rare types commonly argued to have formed in lower-than-solar metallicity asymptotic giant branch (AGB) stars. We find that the Y and Z grains show higher 88Sr/87Sr and more variable 138Ba/136Ba ratios than mainstream (MS) grains. According to FRANEC Torino AGB models, the Si, Sr, and Ba isotopic compositions of our Y and Z grains can be consistently explained if the grains came from low-mass AGB stars with 0.15 Z{$\odot$}\,{$\leq$}\,Z\,{$<$}\,1.00 Z{$\odot$}, in which the 13C neutron exposure for the slow neutron-capture process is greatly reduced with respect to that required by MS grains for a 1.0 Z{$\odot$} AGB star. This scenario is in line with the previous finding based on Ti isotopes, but it fails to explain the indistinguishable Mo isotopic compositions of MS, Y, and Z grains.}, - langid = {english} + abstract = {We report the Sr and Ba isotopic compositions of 18 presolar SiC + grains of types Y (11) and Z (7), rare types commonly argued to + have formed in lower-than-solar metallicity asymptotic giant branch + (AGB) stars. We find that the Y and Z grains show higher 88Sr/87Sr + and more variable 138Ba/136Ba ratios than mainstream (MS) grains. + According to FRANEC Torino AGB models, the Si, Sr, and Ba isotopic + compositions of our Y and Z grains can be consistently explained if + the grains came from low-mass AGB stars with 0.15 Z{$\odot$}\,{$ + \leq$}\,Z\,{$<$}\,1.00 Z{$\odot$}, in which the 13C neutron + exposure for the slow neutron-capture process is greatly reduced + with respect to that required by MS grains for a 1.0 Z{$\odot$} AGB + star. This scenario is in line with the previous finding based on + Ti isotopes, but it fails to explain the indistinguishable Mo + isotopic compositions of MS, Y, and Z grains.}, + langid = {english}, } @article{SiC-2023-HOP-0, - title = {New Constraints for Supernova Models from Presolar Silicon Carbide {{X}} Grains with Very High {\textsuperscript{26}}{{Al}}/{\textsuperscript{27}}{{Al}} Ratios}, - author = {Hoppe, Peter and Leitner, Jan and Pignatari, Marco and Amari, Sachiko}, - year = {2023}, + title = {New Constraints for Supernova Models from Presolar Silicon Carbide {{ + X}} Grains with Very High {$^{26}$}{{Al}}/ {$^{27}$}{{Al}} Ratios}, + author = {Hoppe, Peter and Leitner, Jan and Pignatari, Marco and Amari, + Sachiko}, + year = 2023, month = feb, journal = {The Astrophysical Journal Letters}, volume = {943}, @@ -1953,14 +4499,66 @@ @article{SiC-2023-HOP-0 issn = {2041-8205}, doi = {10.3847/2041-8213/acb157}, urldate = {2023-02-15}, - abstract = {We report C, N, Mg-Al, Si, and S isotope data of six 1--3 {$\mu$}m-sized SiC grains of Type X from the Murchison CM2 chondrite, believed to have formed in the ejecta of core-collapse supernova (CCSN) explosions. Their C, N, and Si isotopic compositions are fully compatible with previously studied X grains. Magnesium is essentially monoisotopic 26Mg which gives clear evidence for the decay of radioactive 26Al. Inferred initial 26Al/27Al ratios are between 0.6 and 0.78 which is at the upper end of previously observed ratios of X grains. Contamination with terrestrial or solar system Al apparently is low or absent, which makes the X grains from this study particularly interesting and useful for a quantitative comparison of Al isotope data with predictions from supernova models. The consistently high 26Al/27Al ratios observed here may suggest that the lower 26Al/27Al ratios of many X grains from the literature are the result of significant Al contamination and in part also of an improper quantification of 26Al. The real dispersion of 26Al/27Al ratios in X grains needs to be explored by future studies. The high observed 26Al/27Al ratios in this work provide a crucial constraint for the production of 26Al in CCSN models. We explored different CCSN models, including both ``classical'' and H ingestion CCSN models. It is found that the classical models cannot account for the high 26Al/27Al ratios observed here; in contrast, H ingestion models are able to reproduce the 26Al/27Al ratios along with C, N, and Si isotopic ratios reasonably well.}, - langid = {english} + abstract = {We report C, N, Mg-Al, Si, and S isotope data of six 1--3 {$\mu$} + m-sized SiC grains of Type X from the Murchison CM2 chondrite, + believed to have formed in the ejecta of core-collapse supernova + (CCSN) explosions. Their C, N, and Si isotopic compositions are + fully compatible with previously studied X grains. Magnesium is + essentially monoisotopic 26Mg which gives clear evidence for the + decay of radioactive 26Al. Inferred initial 26Al/27Al ratios are + between 0.6 and 0.78 which is at the upper end of previously + observed ratios of X grains. Contamination with terrestrial or + solar system Al apparently is low or absent, which makes the X + grains from this study particularly interesting and useful for a + quantitative comparison of Al isotope data with predictions from + supernova models. The consistently high 26Al/27Al ratios observed + here may suggest that the lower 26Al/27Al ratios of many X grains + from the literature are the result of significant Al contamination + and in part also of an improper quantification of 26Al. The real + dispersion of 26Al/27Al ratios in X grains needs to be explored by + future studies. The high observed 26Al/27Al ratios in this work + provide a crucial constraint for the production of 26Al in CCSN + models. We explored different CCSN models, including both + ``classical'' and H ingestion CCSN models. It is found that the + classical models cannot account for the high 26Al/27Al ratios + observed here; in contrast, H ingestion models are able to + reproduce the 26Al/27Al ratios along with C, N, and Si isotopic + ratios reasonably well.}, + langid = {english}, } @article{SiC-2023-NGU-0, - title = {Abundant Presolar Grains and Primordial Organics Preserved in Carbon-Rich Exogenous Clasts in Asteroid {{Ryugu}}}, - author = {Nguyen, Ann N. and Mane, Prajkta and Keller, Lindsay P. and Piani, Laurette and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and Alexander, Conel M. O'D. and Amari, Sachiko and Amelin, Yuri and Bajo, Ken-ichi and Bizzarro, Martin and Bouvier, Audrey and Carlson, Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Dauphas, Nicolas and Davis, Andrew M. and Di Rocco, Tommaso and Fujiya, Wataru and Fukai, Ryota and Gautam, Ikshu and Haba, Makiko K. and Hibiya, Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter and Huss, Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and Ireland, Trevor R. and Ishikawa, Akira and Itoh, Shoichi and Kawasaki, Noriyuki and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten and Komatani, Shintaro and Krot, Alexander N. and Liu, Ming-Chang and Masuda, Yuki and McKeegan, Kevin D. and Morita, Mayu and Motomura, Kazuko and Moynier, Fr{\'e}d{\'e}ric and Nakai, Izumi and Nagashima, Kazuhide and Nesvorn{\'y}, David and Nittler, Larry and Onose, Morihiko and Pack, Andreas and Park, Changkun and Qin, Liping and Russell, Sara S. and Sakamoto, Naoya and Sch{\"o}nb{\"a}chler, Maria and Tafla, Lauren and Tang, Haolan and Terada, Kentaro and Terada, Yasuko and Usui, Tomohiro and Wada, Sohei and Wadhwa, Meenakshi and Walker, Richard J. and Yamashita, Katsuyuki and Yin, Qing-Zhu and Yokoyama, Tetsuya and Yoneda, Shigekazu and Young, Edward D. and Yui, Hiroharu and Zhang, Ai-Cheng and Nakamura, Tomoki and Naraoka, Hiroshi and Noguchi, Takaaki and Okazaki, Ryuji and Sakamoto, Kanako and Yabuta, Hikaru and Abe, Masanao and Miyazaki, Akiko and Nakato, Aiko and Nishimura, Masahiro and Okada, Tatsuaki and Yada, Toru and Yogata, Kasumi and Nakazawa, Satoru and Saiki, Takanao and Tanaka, Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, Sei-ichiro and Yoshikawa, Makoto and Tachibana, Shogo and Yurimoto, Hisayoshi}, - year = {2023}, + title = {Abundant Presolar Grains and Primordial Organics Preserved in + Carbon-Rich Exogenous Clasts in Asteroid {{Ryugu}}}, + author = {Nguyen, Ann N. and Mane, Prajkta and Keller, Lindsay P. and Piani, + Laurette and Abe, Yoshinari and Al{\'e}on, J{\'e}r{\^o}me and + Alexander, Conel M. O'D. and Amari, Sachiko and Amelin, Yuri and Bajo + , Ken-ichi and Bizzarro, Martin and Bouvier, Audrey and Carlson, + Richard W. and Chaussidon, Marc and Choi, Byeon-Gak and Dauphas, + Nicolas and Davis, Andrew M. and Di Rocco, Tommaso and Fujiya, Wataru + and Fukai, Ryota and Gautam, Ikshu and Haba, Makiko K. and Hibiya, + Yuki and Hidaka, Hiroshi and Homma, Hisashi and Hoppe, Peter and Huss + , Gary R. and Ichida, Kiyohiro and Iizuka, Tsuyoshi and Ireland, + Trevor R. and Ishikawa, Akira and Itoh, Shoichi and Kawasaki, + Noriyuki and Kita, Noriko T. and Kitajima, Kouki and Kleine, Thorsten + and Komatani, Shintaro and Krot, Alexander N. and Liu, Ming-Chang and + Masuda, Yuki and McKeegan, Kevin D. and Morita, Mayu and Motomura, + Kazuko and Moynier, Fr{\'e}d{\'e}ric and Nakai, Izumi and Nagashima, + Kazuhide and Nesvorn{\'y}, David and Nittler, Larry and Onose, + Morihiko and Pack, Andreas and Park, Changkun and Qin, Liping and + Russell, Sara S. and Sakamoto, Naoya and Sch{\"o}nb{\"a}chler, Maria + and Tafla, Lauren and Tang, Haolan and Terada, Kentaro and Terada, + Yasuko and Usui, Tomohiro and Wada, Sohei and Wadhwa, Meenakshi and + Walker, Richard J. and Yamashita, Katsuyuki and Yin, Qing-Zhu and + Yokoyama, Tetsuya and Yoneda, Shigekazu and Young, Edward D. and Yui, + Hiroharu and Zhang, Ai-Cheng and Nakamura, Tomoki and Naraoka, + Hiroshi and Noguchi, Takaaki and Okazaki, Ryuji and Sakamoto, Kanako + and Yabuta, Hikaru and Abe, Masanao and Miyazaki, Akiko and Nakato, + Aiko and Nishimura, Masahiro and Okada, Tatsuaki and Yada, Toru and + Yogata, Kasumi and Nakazawa, Satoru and Saiki, Takanao and Tanaka, + Satoshi and Terui, Fuyuto and Tsuda, Yuichi and Watanabe, Sei-ichiro + and Yoshikawa, Makoto and Tachibana, Shogo and Yurimoto, Hisayoshi}, + year = 2023, month = jul, journal = {Science Advances}, volume = {9}, @@ -1969,15 +4567,35 @@ @article{SiC-2023-NGU-0 issn = {2375-2548}, doi = {10.1126/sciadv.adh1003}, urldate = {2024-05-30}, - abstract = {Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC ({\textasciitilde}235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2\%), and organics with C isotopic anomalies (0.2\%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugu's rubble pile origin. , Exogenic primitive clasts in Ryugu samples have remarkable abundances of presolar grains and isotopically anomalous organics.}, - langid = {english} + abstract = {Preliminary analyses of asteroid Ryugu samples show kinship to + aqueously altered CI (Ivuna-type) chondrites, suggesting similar + origins. We report identification of C-rich, particularly primitive + clasts in Ryugu samples that contain preserved presolar silicate + grains and exceptional abundances of presolar SiC and isotopically + anomalous organic matter. The high presolar silicate abundance (104 + ppm) indicates that the clast escaped extensive alteration. The 5 + to 10 times higher abundances of presolar SiC (\textasciitilde 235 + ppm), N-rich organic matter, organics with N isotopic anomalies + (1.2\%), and organics with C isotopic anomalies (0.2\%) in the + primitive clasts compared to bulk Ryugu suggest that the clasts + formed in a unique part of the protoplanetary disk enriched in + presolar materials. These clasts likely represent previously + unsampled outer solar system material that accreted onto Ryugu + after aqueous alteration ceased, consistent with Ryugu's rubble + pile origin. , Exogenic primitive clasts in Ryugu samples have + remarkable abundances of presolar grains and isotopically anomalous + organics.}, + langid = {english}, } @article{SiC-2024-HOP-0, - title = {Isotope Studies of Presolar Silicon Carbide Grains from Supernovae: New Constraints for Hydrogen-Ingestion Supernova Models}, - shorttitle = {Isotope Studies of Presolar Silicon Carbide Grains from Supernovae}, - author = {Hoppe, Peter and Leitner, Jan and Pignatari, Marco and Amari, Sachiko}, - year = {2024}, + title = {Isotope Studies of Presolar Silicon Carbide Grains from Supernovae: { + {New}} Constraints for Hydrogen-Ingestion Supernova Models}, + shorttitle = {Isotope Studies of Presolar Silicon Carbide Grains from + Supernovae}, + author = {Hoppe, Peter and Leitner, Jan and Pignatari, Marco and Amari, + Sachiko}, + year = 2024, month = jun, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {532}, @@ -1986,16 +4604,43 @@ @article{SiC-2024-HOP-0 issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stae1523}, urldate = {2025-03-24}, - abstract = {ABSTRACT We report isotope data for C, N, Al, Si, and S of 33 presolar SiC and Si3N4 grains (0.3--1.6\,\${\textbackslash}mu\$m) of Type X, C, D, and N from the Murchison CM2 meteorite of likely core-collapse supernova (CCSN) origin which we discuss together with data of six SiC X grains from an earlier study. The isotope data are discussed in the context of hydrogen ingestion supernova (SN) models. We have modified previously used ad-hoc mixing schemes in that we considered (i) heterogeneous H ingestion into the He shell of the pre-SN star, (ii) a variable C-N fractionation for the condensation of SiC grains in the SN ejecta, and (iii) smaller mass units for better fine-tuning. With our modified ad-hoc mixing approach over small scales (0.2--0.4\,M{$\odot$}), with major contributions from the O-rich O/nova zone, we find remarkably good fits (within a few~per\,cent) for 12C/13C, 26Al/27Al, and 29Si/28Si ratios. The 14N/15N ratio of SiC grains can be well matched if variable C-N fractionation is considered. However, the Si3N4 isotope data point to overproduction of 15N in hydrogen ingestion CCSN models and lower C-N fractionation during SiC condensation than applied here. Our ad-hoc mixing approach based on current CCSN models suggests that the O-rich O/nova zone, which uniquely combines explosive H- and He-burning signatures, is favourable for SiC and Si3N4 formation. The effective range of C/O abundance variations in the He shell triggered by H ingestion events in the massive star progenitor is currently not well constrained and needs further investigation.}, - copyright = {https://creativecommons.org/licenses/by/4.0/}, - langid = {english} + abstract = {ABSTRACT We report isotope data for C, N, Al, Si, and S of 33 + presolar SiC and Si3N4 grains (0.3--1.6\,\$\textbackslash mu\$m) of + Type X, C, D, and N from the Murchison CM2 meteorite of likely + core-collapse supernova (CCSN) origin which we discuss together + with data of six SiC X grains from an earlier study. The isotope + data are discussed in the context of hydrogen ingestion supernova + (SN) models. We have modified previously used ad-hoc mixing schemes + in that we considered (i) heterogeneous H ingestion into the He + shell of the pre-SN star, (ii) a variable C-N fractionation for the + condensation of SiC grains in the SN ejecta, and (iii) smaller mass + units for better fine-tuning. With our modified ad-hoc mixing + approach over small scales (0.2--0.4\,M{$\odot$}), with major + contributions from the O-rich O/nova zone, we find remarkably good + fits (within a few per\,cent) for 12C/13C, 26Al/27Al, and 29Si/28Si + ratios. The 14N/15N ratio of SiC grains can be well matched if + variable C-N fractionation is considered. However, the Si3N4 + isotope data point to overproduction of 15N in hydrogen ingestion + CCSN models and lower C-N fractionation during SiC condensation + than applied here. Our ad-hoc mixing approach based on current CCSN + models suggests that the O-rich O/nova zone, which uniquely + combines explosive H- and He-burning signatures, is favourable for + SiC and Si3N4 formation. The effective range of C/O abundance + variations in the He shell triggered by H ingestion events in the + massive star progenitor is currently not well constrained and needs + further investigation.}, + langid = {english}, } @article{SiC-2024-LIU-0, - title = {Explosive {{Nucleosynthesis}} in {{Core-collapse Type II Supernovae}}: {{Insights}} from {{New C}}, {{N}}, {{Si}}, and {{Al}}--{{Mg Isotopic Compositions}} of {{Presolar Grains}}}, - shorttitle = {Explosive {{Nucleosynthesis}} in {{Core-collapse Type II Supernovae}}}, - author = {Liu, Nan and Alexander, Conel M. O'D. and Meyer, Bradley S. and Nittler, Larry R. and Wang, Jianhua and Stroud, Rhonda M.}, - year = {2024}, + title = {Explosive {{Nucleosynthesis}} in {{Core-collapse Type II Supernovae}} + : {{Insights}} from {{New C}}, {{N}}, {{Si}}, and {{Al}}--{{Mg + Isotopic Compositions}} of {{Presolar Grains}}}, + shorttitle = {Explosive {{Nucleosynthesis}} in {{Core-collapse Type II + Supernovae}}}, + author = {Liu, Nan and Alexander, Conel M. O'D. and Meyer, Bradley S. and + Nittler, Larry R. and Wang, Jianhua and Stroud, Rhonda M.}, + year = 2024, month = jan, journal = {The Astrophysical Journal Letters}, volume = {961}, @@ -2004,13 +4649,40 @@ @article{SiC-2024-LIU-0 issn = {2041-8205, 2041-8213}, doi = {10.3847/2041-8213/ad18c7}, urldate = {2024-05-30}, - abstract = {Abstract We report C, N, Si, and Al--Mg isotope data for 39 presolar X silicon carbide (SiC) and four silicon nitride grains---a group of presolar grains that condensed in the remnants of core-collapse Type II supernovae (CCSNe)---isolated from the Murchison meteorite. Energy dispersive X-ray data were used to determine the Mg and Al contents of the X SiC grains for comparison with the Mg/Al ratios determined by secondary ion mass spectroscopy (SIMS). Previous SIMS studies have used O-rich standards in the absence of alternatives. In this study, the correlated isotopic and elemental data of the X SiC grains enabled accurate determination of the initial 26 Al/ 27 Al ratios for the grains. Our new grain data suggest that (i) the literature data for X grains are affected to varying degrees by asteroidal/terrestrial contamination, and (ii) the Al/Mg ratios in SiC are a factor of 2 (with {\textpm}6\% 1 {$\sigma$} uncertainties) lower than estimated based on the SIMS analyses that used O-rich standards. The lowered Al/Mg ratios result in proportionally higher inferred initial 26 Al/ 27 Al ratios for presolar SiC grains. In addition, the suppression of asteroidal/terrestrial contamination in this study leads to the observation of negative trends for 12 C/ 13 C-- 30 Si/ 28 Si and 26 Al/ 27 Al-- 30 Si/ 28 Si among our CCSN grains. We discuss these isotope trends in the light of explosive CCSN nucleosynthesis models, based on which we provide new insights into several nontraditional CCSN nucleosynthesis processes, including explosive H burning, the existence of a C/Si zone in the outer regions of CCSNe, and neutrino--nucleus reactions in deep CCSN regions.} + abstract = {Abstract We report C, N, Si, and Al--Mg isotope data for 39 + presolar X silicon carbide (SiC) and four silicon nitride + grains---a group of presolar grains that condensed in the remnants + of core-collapse Type II supernovae (CCSNe)---isolated from the + Murchison meteorite. Energy dispersive X-ray data were used to + determine the Mg and Al contents of the X SiC grains for comparison + with the Mg/Al ratios determined by secondary ion mass spectroscopy + (SIMS). Previous SIMS studies have used O-rich standards in the + absence of alternatives. In this study, the correlated isotopic and + elemental data of the X SiC grains enabled accurate determination + of the initial 26 Al/ 27 Al ratios for the grains. Our new grain + data suggest that (i) the literature data for X grains are affected + to varying degrees by asteroidal/terrestrial contamination, and + (ii) the Al/Mg ratios in SiC are a factor of 2 (with \textpm 6\% 1 + {$\sigma$} uncertainties) lower than estimated based on the SIMS + analyses that used O-rich standards. The lowered Al/Mg ratios + result in proportionally higher inferred initial 26 Al/ 27 Al + ratios for presolar SiC grains. In addition, the suppression of + asteroidal/terrestrial contamination in this study leads to the + observation of negative trends for 12 C/ 13 C-- 30 Si/ 28 Si and 26 + Al/ 27 Al-- 30 Si/ 28 Si among our CCSN grains. We discuss these + isotope trends in the light of explosive CCSN nucleosynthesis + models, based on which we provide new insights into several + nontraditional CCSN nucleosynthesis processes, including explosive + H burning, the existence of a C/Si zone in the outer regions of + CCSNe, and neutrino--nucleus reactions in deep CCSN regions.}, } @article{SiC-2025-STE-0, - title = {Correlated {{Molybdenum}}, {{Ruthenium}}, and {{Barium Isotope Anomalies}} in {{Presolar Silicon Carbide Grains}}}, - author = {Stephan, Thomas and Hoppe, Peter and Davis, Andrew M. and Korsmeyer, Julie M. and Regula, Andrew and Richards, Hannah E.}, - year = {2025}, + title = {Correlated {{Molybdenum}}, {{Ruthenium}}, and {{Barium Isotope + Anomalies}} in {{Presolar Silicon Carbide Grains}}}, + author = {Stephan, Thomas and Hoppe, Peter and Davis, Andrew M. and Korsmeyer, + Julie M. and Regula, Andrew and Richards, Hannah E.}, + year = 2025, month = mar, journal = {The Astrophysical Journal}, volume = {981}, @@ -2019,5 +4691,71 @@ @article{SiC-2025-STE-0 issn = {0004-637X, 1538-4357}, doi = {10.3847/1538-4357/adb308}, urldate = {2025-03-24}, - abstract = {Abstract We have analyzed molybdenum, ruthenium, and barium isotopes simultaneously in 55 individual presolar silicon carbide (SiC) grains from the Murchison CM2 meteorite using the Chicago Instrument for Laser Ionization (or CHILI). Most grains show clear s -process signatures, which are strongly correlated for molybdenum and ruthenium. For all three elements, we provide estimates for s -process contributions from low-mass AGB stars with unprecedented precision. Variations in s -process production observed for some nuclides reflect a strong dependence on physical properties, neutron density, temperature, and timing, affecting various s -process branch points. Significant contamination can be excluded for a majority of grains. Instead, distributions along mixing lines in three-isotope diagrams reflect mixing between initial parent star material and matter synthesized in the star. The results suggest that the ratios between p - and r -process isotopes of molybdenum, ruthenium, and barium in presolar SiC from many parent stars are the same as the ones inferred for the solar system. This indicates that the products of these processes were well mixed by the time the molecular cloud collapsed to form the stars that eventually grew the SiC grains, and that this mixture did not change between formation of the precursor stars and formation of the Sun.} + abstract = {Abstract We have analyzed molybdenum, ruthenium, and barium + isotopes simultaneously in 55 individual presolar silicon carbide + (SiC) grains from the Murchison CM2 meteorite using the Chicago + Instrument for Laser Ionization (or CHILI). Most grains show clear + s -process signatures, which are strongly correlated for molybdenum + and ruthenium. For all three elements, we provide estimates for s + -process contributions from low-mass AGB stars with unprecedented + precision. Variations in s -process production observed for some + nuclides reflect a strong dependence on physical properties, + neutron density, temperature, and timing, affecting various s + -process branch points. Significant contamination can be excluded + for a majority of grains. Instead, distributions along mixing lines + in three-isotope diagrams reflect mixing between initial parent + star material and matter synthesized in the star. The results + suggest that the ratios between p - and r -process isotopes of + molybdenum, ruthenium, and barium in presolar SiC from many parent + stars are the same as the ones inferred for the solar system. This + indicates that the products of these processes were well mixed by + the time the molecular cloud collapsed to form the stars that + eventually grew the SiC grains, and that this mixture did not + change between formation of the precursor stars and formation of + the Sun.}, +} + +@article{SiC-2026-MAR-0, + title = {Isotopic {{Compositions}} and {{Elemental Abundances}} of {{Chromium} + } in {{Presolar Silicon Carbide Grains}} from {{Asymptotic Giant + Branch Stars}}}, + author = {Marhas, Kuljeet K. and Sanghani, Manish N. and Messenger, Scott R. + and Mitra, Antariksha and Mishra, Ritesh K.}, + year = 2026, + month = feb, + journal = {ApJ}, + volume = {997}, + number = {2}, + pages = {275}, + issn = {0004-637X, 1538-4357}, + doi = {10.3847/1538-4357/ae2bf6}, + urldate = {2026-08-26}, + abstract = {Abstract Isotopes of chromium (Cr) and other iron-group elements + are predominantly made in the inner shells of supernovae and are + later reprocessed via the slow neutron capture process ( s + -process) in asymptotic giant branch (AGB) stars. Nucleosynthetic + models of low-mass, solar metallicity AGB stars yield significant + overproduction of 54 Cr ( {$\delta$} 54 Cr values~{$\sim~$}+160‰) + with limited variations in other Cr isotopes, relative to solar + system values. Here we report Cr, C, and N isotopic compositions of + 16 individual presolar silicon carbide (SiC) grains of the KJG + series (1.5--3 {$\mu$} m) from the Murchison (CM2.0) meteorite. 12 + C/ 13 C and 14 N/ 15 N ratios of the 14 mainstream SiC grains range + from 29 to 108 and 259 to 7800, respectively. These C, N isotopic + compositions are consistent with their formation in red giant and + AGB stars. Two types of AB grains could have originated in a J-type + C-star (AB2) and a type-II supernova (AB). The majority of + mainstream grains display close-to-solar Cr isotopic compositions, + indicating the Cr was not significantly processed within their + parent AGB stars. A mainstream SiC grain with relatively high 54 Cr + enrichment of {$\delta$} 54 Cr~{$\sim~$}700‰ likely originated from + a very low metallicity parent star based on the stellar + nucleosynthesis model (FRUITY). We consider the plausible origin of + this grain from Galactic halo stars, migration from the outer + Galactic disk, and other scenarios. Elemental Cr concentrations of + the grains vary from {$\sim$}1 to 9 ppm, with 75\% of the grains + displaying an average concentration of {$\sim$}2 ppm. Cr + concentration does not vary significantly with grain size, + suggesting that the Cr in the SiC grains condensed during grain + formation and was not implanted at a later stage.}, } diff --git a/database/references.json b/database/references.json index 48e0889..20d53a9 100644 --- a/database/references.json +++ b/database/references.json @@ -873,5 +873,19 @@ "Reference - full": "Groopman E. E. and Nittler L. R. (2018) Correlated XANES, TEM, and NanoSIMS of presolar graphite grains. Geochim. Cosmochim. Acta 221, 219\u2013236.", "DOI": "10.1016/j.gca.2017.02.011", "Comments": "" + }, + "SiC-2025-NGU-0": { + "Number of grains": 58, + "Reference - short": "Nguyen et al. (2025) NatAs 9:1812", + "Reference - full": "Nguyen A. N., Seifert L. B., Shimizu K., Thomas-Keprta K., Le L., Keller L. P., Clemett S. J., Rahman Z., Barnes J. J., Connolly H. C., Jr., and Lauretta D. S. (2025) Abundant supernova dust and heterogeneous aqueous alteration revealed by stardust in two lithologies of asteroid Bennu. Nature Astron. 9, 1812\u20131820.", + "DOI": "10.1038/s41550-025-02688-3", + "Comments": "" + }, + "SiC-2026-MAR-0": { + "Number of grains": 16, + "Reference - short": "Marhas et al. (2026) ApJ 997:275", + "Reference - full": "Marhas K. K., Sanghani M. N., Messenger S. R., Mitra A., and Mishra R. K. (2026) Isotopic compositions and elemental abundances of chromium in presolar silicon carbide grains from asymptotic giant branch stars. Astrophys. J. 997, 275 (12pp).", + "DOI": "10.3847/1538-4357/ae2bf6", + "Comments": "d(54Cr/52Cr] data are corrected using solar d(54Fe/56Fe) ratio" } } diff --git a/docs/maintainer/db_addition.md b/docs/maintainer/db_addition.md index 3a8cd00..f6be71f 100644 --- a/docs/maintainer/db_addition.md +++ b/docs/maintainer/db_addition.md @@ -62,7 +62,6 @@ excel_file = Path( mt.append_reference_json(excel_file) ``` - Note that we assume that the information is in a tab called "References". If not, please specify the tab name using the `tab_name` argument. This will add the references to the `references.json` file in the `database` directory of the repository. @@ -104,7 +103,11 @@ This file is used by `pgdtools` to know which databases are available and where to get them from. A new release must be added to this file. This can be done automatically with the maintainer tools. -You will need the excel file (as above) and the DOI of the release. + +### Database release has a Zenodo DOI + +If you have a Zenodo DOI, +you will need the excel file (as above) and the DOI of the release. ```python from pathlib import Path @@ -118,10 +121,37 @@ doi = "10.5281/zenodo.1234567" # replace with the DOI of the release mt.append_to_db_json(excel_file, doi, db_json=db_json) ``` +### Database release has an Astromat DOI and a Zenodo release + +If you have an Astromat DOI and have released the database on Zenodo as well, +you need the DOI and and the Zenodo record, +which you can find in the download link of the databse. +For example, The zenodo record for the download link +`https://zenodo.org/records/20317007/files/PGD_SiC_2026-05-19.csv?download=1` +would be `20317007`. + +Then run: + +```python +from pathlib import Path + +import pgdtools.maintainer as mt + +excel_file = Path("PGD_SiC_2023-07-22.xlsx") +db_json = Path("db.json") + +doi = "10.5281/ABCD.1234567" # replace with the DOI of the release +zenodo_record = "20317007" + +mt.append_to_db_json(excel_file, doi, zenodo_record=zenodo_record, db_json=db_json) +``` + If the current database is not yet in the `db.json` file, it will be appended. Otherwise, a warning will be raised and the `db.json` file will not be modified. +### Notes + If you run `pgdtools` from a cloned GitHub branch, the `db_json` keyword can be omitted. In this case, the `db.json` file in the repository will be updated. @@ -135,7 +165,8 @@ If this is not the case, you can use the `url` and `db_name` keywords. !!! info "Database on Astromat but cross-listed on Zenodo" If the doi of the database does not contain the word `zenodo`, - it was not minted by Zenodo and was most likely created by Astromat (IEDA). + it was not minted by Zenodo and the above procedure assumes + that it was released on Astromat. If the database is cross-referenced on Zenodo, hover over the Zenodo download link and extract the record ID manually. This record ID is the number after `record/` and before `files` in the URL. diff --git a/src/pgdtools/maintainer/excel_tools.py b/src/pgdtools/maintainer/excel_tools.py index 243e8f4..83565a2 100644 --- a/src/pgdtools/maintainer/excel_tools.py +++ b/src/pgdtools/maintainer/excel_tools.py @@ -30,7 +30,7 @@ def append_to_db_json( Currently, only releases on Zenodo are supported for SiC and Graphite grains. If the DOI does not contain the word `zenodo`, it refers likely to another archive - (Astromat - IEDA) and the `zenodo_record` number is required. + (Astromat - IEDA c) and the `zenodo_record` number is required. :param excel_file: Path to the Excel file. :param doi: DOI of the database. @@ -81,7 +81,7 @@ def append_to_db_json( f"https://zenodo.org/record/{doi.split('.')[-1]}/files/" f"{excel_file.with_suffix('.csv').name}" ) - elif zenodo_record is not None and "IEDA" in doi: # Astromat/Zenodo cross release + elif zenodo_record is not None: # Astromat/Zenodo cross release released_on = "Astromat" if url is None: url = ( @@ -90,8 +90,7 @@ def append_to_db_json( ) else: raise NotImplementedError( - "Only Zenodo releases and Astromat (IEDA) releases that are " - "cross-released on Zenodo are currently supported." + "If you do not provie a zenodo DOI, please specify the Zenodo record." ) # read the VersionHistory sheet for info where the correct date is displayed