Barium isotopes in individual presolar silicon carbide grains from the Murchison meteorite

Michael R Savina, Andrew M Davis, C Emil Tripa, Michael J Pellin, Robert N Clayton, Roy S Lewis, Sachiko Amari, Roberto Gallino, Maria Anna Lugaro

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Abstract

Barium isotopic compositions of single 2.3-5.3 grit 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.
Original languageEnglish
Pages (from-to)3201 - 3214
Number of pages14
JournalGeochimica et Cosmochimica Acta
Volume67
Issue number17
Publication statusPublished - 2003
Externally publishedYes

Cite this

Savina, M. R., Davis, A. M., Tripa, C. E., Pellin, M. J., Clayton, R. N., Lewis, R. S., Amari, S., Gallino, R., & Lugaro, M. A. (2003). Barium isotopes in individual presolar silicon carbide grains from the Murchison meteorite. Geochimica et Cosmochimica Acta, 67(17), 3201 - 3214.