Presolar Grains in Meteorites and Their Compositions |
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Authors: | Ulrich Ott |
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Institution: | (1) Max-Planck-Institut für Chemie, Joh.-J.-Becher-Weg 27, 55128 Mainz, Germany |
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Abstract: | Small amounts of pre-solar “stardust” grains have survived in the matrices of primitive meteorites and interplanetary dust
particles. These grains—formed directly in the outflows of or from the ejecta of stars—include thermally and chemically refractory
carbon materials such as diamond, graphite and silicon carbide; as well as refractory oxides and nitrides. Pre-solar silicates,
which have only recently been identified, are the most abundant type except for possibly diamond. The detailed study with
modern analytical tools, of isotopic signatures in particular, provides highly accurate and detailed information with regard
to stellar nucleosynthesis and grain formation in stellar atmospheres. Important stellar sources are Red Giant (RG) and Asymptotic
Giant Branch (AGB) stars, with supernova contributions apparently small. The survival of those grains puts constraints on
conditions they were exposed to in the interstellar medium and in the early solar system. |
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Keywords: | Interstellar grains Nucleosynthesis Grain formation Solar System Meteorites |
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