Si isotope homogeneity of the solar nebula

Journal Article · Fri Dec 20 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/779/2/123· OSTI ID:22348459

Pringle, Emily A.; Savage, Paul S.; Moynier, Frédéric ^[1]; Jackson, Matthew G. ^[2]; Barrat, Jean-Alix ^[3]

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1. Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130 (United States)
2. Department of Earth Science, University of California, Santa Barbara, CA 93109 (United States)
3. Université Européenne de Bretagne, Université de Brest, CNRS UMR 6538 (Domaines Océaniques), I.U.E.M., Place Nicolas Copernic, F-29280 Plouzané Cedex (France)

The presence or absence of variations in the mass-independent abundances of Si isotopes in bulk meteorites provides important clues concerning the evolution of the early solar system. No Si isotopic anomalies have been found within the level of analytical precision of 15 ppm in {sup 29}Si/{sup 28}Si across a wide range of inner solar system materials, including terrestrial basalts, chondrites, and achondrites. A possible exception is the angrites, which may exhibit small excesses of {sup 29}Si. However, the general absence of anomalies suggests that primitive meteorites and differentiated planetesimals formed in a reservoir that was isotopically homogenous with respect to Si. Furthermore, the lack of resolvable anomalies in the calcium-aluminum-rich inclusion measured here suggests that any nucleosynthetic anomalies in Si isotopes were erased through mixing in the solar nebula prior to the formation of refractory solids. The homogeneity exhibited by Si isotopes may have implications for the distribution of Mg isotopes in the solar nebula. Based on supernova nucleosynthetic yield calculations, the expected magnitude of heavy-isotope overabundance is larger for Si than for Mg, suggesting that any potential Mg heterogeneity, if present, exists below the 15 ppm level.

• OSTI ID: 22348459
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 779; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
ACCURACY
ACHONDRITES
ALUMINIUM
ASTEROIDS
CHONDRITES
DISTRIBUTION
EXCEPTIONS
MAGNESIUM ISOTOPES
MASS
NUCLEOSYNTHESIS
PLANETS
PROTOPLANETS
REFRACTORIES
SATELLITES
SILICON 28
SILICON 29
SOLAR NEBULA
SOLAR SYSTEM
SOLIDS