Speaker
Description
The extremely metal-poor dwarf galaxy Sextans A provides a unique laboratory for investigating the evolution of asymptotic giant branch (AGB) stars under conditions resembling those of the early Universe. In this contribution, I present a characterization of the evolved stellar population of Sextans A based on a comparison between JWST photometry and state-of-the-art stellar evolution and dust-formation models. This approach enables a comprehensive characterization of the observed sources, in terms of distribution of mass, chemical composition, and formation epoch of the progenitors, as well as the current evolutionary stage and dust production rate.
Although the present analysis is based on single-epoch observations, stellar variability is expected to play a key role in shaping the observed properties of AGB stars and in the interpretation of their luminosities, mass-loss rates, and dust production efficiencies. I will also briefly discuss the possible impact of binary interactions, which may modify mass-loss histories and circumstellar dust properties, contributing to some of the most peculiar dusty sources.
In this context, the AGB population of Sextans A offers a valuable opportunity to explore the possible connections between chemical composition, dust production, stellar variability, and binary interaction, contributing to a more comprehensive characterization of AGB populations in galaxies.