Slow Neutron-Capture Process: Low-mass AGB stars and presolar silicon carbide grains

TL;DR

This paper reviews isotope studies of presolar silicon carbide grains from low-mass AGB stars, emphasizing their role in understanding the slow neutron-capture process and constraining stellar parameters through isotope analysis.

Contribution

It highlights the significance of presolar grain isotope data in providing new insights into AGB stellar processes and nuclear reaction rates.

Findings

Presolar SiC grains predominantly originate from low-mass AGB stars.

Isotope signatures in grains help constrain stellar parameters and nuclear reactions.

Heavy-element isotopes in grains inform models of the s-process in stars.

Abstract

Presolar grains are microscopic dust grains that formed in the stellar winds or explosions of ancient stars that died before the formation of the solar system. The majority (~90% in number) of presolar silicon carbide (SiC) grains, including types mainstream (MS), Y, and Z, came from low-mass C-rich asymptotic giant branch (AGB) stars, which is supported by the ubiquitous presence of SiC dust observed in the circumstellar envelope of AGB stars and the signatures of slow neutron-capture process preserved in these grains. Here, we review the status of isotope studies of presolar AGB SiC grains with an emphasis on heavy-element isotopes and highlight the importance of presolar grain studies for nuclear astrophysics. We discuss the sensitives of different types of nuclei to varying AGB stellar parameters and how their abundances in presolar AGB SiC grains can be used to provide independent, detailed constraints on stellar parameters, including 13C formation, stellar temperature, and nuclear reaction rates.