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Interstellar SiC with unusual isotopic compositions - Grains from a supernova?Results are presented from an ion microprobe mass spectrometric analyses of five SiC grains from the Murchison carbonaceous meteorite. Unlike most interstellar SiC grains from primitive meteorites, the five grains from the Murchison meteorite show large excesses of C-12 (up to 28 times solar) and N-15 (up to 22 times solar), depletion in Si-29 and Si-30 (up to 59 percent), Al-26/Al-27 ratios between 0.1 and 0.6, and Ti-49 excesses up to 95 percent; in addition, one grain has a large Ca-44 excess (300 percent). The Ca and Ti anomalies point toward explosive nucleosynthesis in supernovae and the in situ decay of the radioactive precursors Ti-44 and V-49 in SiC grains formed in supernova ejecta. However, there is no simple formation scenario that can give a consistent explanation for the isotopic compositions of these grains.
Document ID
19920066815
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Amari, Sachiko
(Washington University Saint Louis, MO; Chicago, University, IL, United States)
Hoppe, Peter
(Washington University Saint Louis, MO; Bern, Universitaet, Switzerland)
Zinner, Ernst
(Washington University Saint Louis, MO, United States)
Lewis, Roy S.
(Chicago, University IL, United States)
Date Acquired
August 15, 2013
Publication Date
August 1, 1992
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 394
Issue: 2 Au
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
92A49439
Funding Number(s)
CONTRACT_GRANT: NAG9-55
CONTRACT_GRANT: NAG9-52
Distribution Limits
Public
Copyright
Other

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