Asymptotic Giant Branch Variables in Nearby Galaxies

TL;DR

This paper reviews recent infrared observations of AGB variable stars in nearby galaxies, highlighting their roles as distance indicators and their significance in understanding galaxy evolution and chemical enrichment.

Contribution

It provides new insights into the properties and evolution of luminous AGB variables across different stellar populations in the Local Group and beyond.

Findings

AGB variables are effective distance indicators rivaling Cepheids.

Luminous AGB stars are key to understanding galaxy light and chemical enrichment.

Rapid evolution of luminous AGB stars remains poorly understood.

Abstract

Certain types of large amplitude AGB variable are proving to be powerful distance indicators that will rival Cepheids in the JWST era of high precision infrared photometry. These are predominantly found in old populations and have low mass progenitors. At the other end of the AGB mass-scale, large amplitude variables, particularly those undergoing hot bottom burning, are the most luminous representatives of their population. These stars are less than one Gyr old, are often losing mass copiously and are vital to our understanding of the integrated light of distant galaxies as well as to chemical enrichment. However, the evolution of such very luminous AGB variables is rapid and remains poorly understood. Here I discuss recent infrared observations of both low- and intermediate-mass Mira variables in the Local Group and beyond.