Origin of Large Meteoritic SiC Stardust Grains in Metal-rich AGB Stars
| Autor: | Blanka Világos, Melanie Hampel, G. Tagliente, Valentina D'Orazi, F. Dell'Agli, U. Battino, Paolo Ventura, Josef Hron, Gyula M. Szabó, Amanda I. Karakas, Reto Trappitsch, Claudio B. Pereira, Larry R. Nittler, Maria Schönbächler, Marco Pignatari, Mattias Ek, B. Cseh, Maria Lugaro, A. Tattersall |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Metallicity FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences Supernova Stars Astrophysics - Solar and Stellar Astrophysics Meteorite Space and Planetary Science Nucleosynthesis 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Circumstellar dust Asymptotic giant branch Astrophysics::Earth and Planetary Astrophysics s-process 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| Zdroj: | The Astrophysical Journal |
| ISSN: | 1538-4357 0004-637X 0067-0049 0004-6361 2041-8205 |
| DOI: | 10.3847/1538-4357/ab9e74 |
| Popis: | Stardust grains that originated in ancient stars and supernovae are recovered from meteorites and carry the detailed composition of their astronomical sites of origin. We present evidence that the majority of large ($\mu$m-sized) meteoritic silicon carbide (SiC) grains formed in C-rich asymptotic giant branch (AGB) stars that were more metal-rich than the Sun. In the framework of the slow neutron-captures (the s process) that occurs in AGB stars the lower-than-solar 88Sr/86Sr isotopic ratios measured in the large SiC grains can only be accompanied by Ce/Y elemental ratios that are also lower than solar, and predominately observed in metal-rich barium stars - the binary companions of AGB stars. Such an origin suggests that these large grains represent the material from high-metallicity AGB stars needed to explain the s-process nucleosynthesis variations observed in bulk meteorites (Ek et al. 2020). In the outflows of metal-rich, C-rich AGB stars SiC grains are predicted to be small ($\simeq$ 0.2 $\mu$m-sized); large ($\simeq$ $\mu$m-sized) SiC grains can grow if the number of dust seeds is two to three orders of magnitude lower than the standard value of $10^{-13}$ times the number of H atoms. We therefore predict that with increasing metallicity the number of dust seeds might decrease, resulting in the production of larger SiC grains. Comment: accepted for publication in The Astrophysical Journal |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|