On the mass and metallicity distribution of parent AGB stars of presolar SiC

TL;DR

This study uses a chemo-dynamical model to identify the likely mass and metallicity of AGB stars that produced presolar SiC grains incorporated into the Solar System, revealing they mainly originated from stars around 2 solar masses with solar metallicity.

Contribution

It provides the first detailed modeling-based estimate of the mass and metallicity distribution of AGB stars that contributed presolar SiC grains to the Solar System.

Findings

Presolar SiC grains mainly originated from AGB stars of about 2 solar masses.

These parent stars had metallicities close to solar.

The results explain the observed grain-size distribution in meteorites.

Abstract

The vast majority (>=90%) of presolar SiC grains identified in primitive meteorites are relics of ancient asymptotic giant branch (AGB) stars, whose ejecta were incorporated into the Solar System during its formation. Detailed characterization of these ancient stardust grains has revealed precious information on mixing processes in AGB interiors in great detail. However, the mass and metallicity distribution of their parent stars still remains ambiguous, although such information is crucial to investigating the slow neutron capture process, whose efficiency is mass- and metallicity-dependent. Using a well-known Milky Way chemo-dynamical model, we follow the evolution of the AGB stars that polluted the Solar System at 4.57 Gyr ago and weighted the stars based on their SiC dust productions. We find that presolar SiC in the Solar System predominantly originated from AGB stars with M~2 Msun and Z~Zsun. Our finding well explains the grain-size distribution of presolar SiC identified in situ in primitive meteorites. Moreover, it provides complementary results to very recent papers dealing with the characterization of parent stars of presolar SiC.