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Origin of Large Meteoritic SiC Stardust Grains in Metal-rich AGB Stars

Schönb chler, Maria; Dell'Agli, Flavia; D'Orazi, Valentina; Lugaro, Maria; Cseh, Borbála; Világos, Blanka; Karakas, Amanda I.; Ventura, Paolo; Dell’Agli, Flavia; Trappitsch, Reto; Hampel, Melanie; D’Orazi, Valentina; Pereira, Claudio B.; Tagliente, Giuseppe; Szabó, Gyula M.; Pignatari, Marco; Battino, Umberto; Tattersall, Ashley; Ek, Mattias; Schönbächler, Maria; Hron, Josef; Nittler, Larry R.

Authors

Maria Schönb chler

Flavia Dell'Agli

Valentina D'Orazi

Maria Lugaro

Borbála Cseh

Blanka Világos

Amanda I. Karakas

Paolo Ventura

Flavia Dell’Agli

Reto Trappitsch

Melanie Hampel

Valentina D’Orazi

Claudio B. Pereira

Giuseppe Tagliente

Gyula M. Szabó

Umberto Battino

Ashley Tattersall

Mattias Ek

Maria Schönbächler

Josef Hron

Larry R. Nittler



Abstract

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 (μm-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 occur 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. In the outflows of metal-rich, C-rich AGB stars, SiC grains are predicted to be small (≃0.2 μm); large (≃μm-sized) SiC grains can grow if the number of dust seeds is 2-3 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.

Citation

Dell'Agli, F., D'Orazi, V., Schönb chler, M., Lugaro, M., Cseh, B., Világos, B., …Nittler, L. R. (2020). Origin of Large Meteoritic SiC Stardust Grains in Metal-rich AGB Stars. The Astrophysical journal, 898(2), https://doi.org/10.3847/1538-4357/ab9e74

Journal Article Type Article
Acceptance Date Jun 17, 2020
Online Publication Date Jul 28, 2020
Publication Date Aug 1, 2020
Deposit Date Aug 1, 2020
Publicly Available Date Jul 29, 2021
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 898
Issue 2
Article Number 96
DOI https://doi.org/10.3847/1538-4357/ab9e74
Keywords Asymptotic giant branch stars; Circumstellar dust; Stellar abundances; Chemically peculiar stars
Public URL https://hull-repository.worktribe.com/output/3551033
Publisher URL https://iopscience.iop.org/article/10.3847/1538-4357/ab9e74