Red Supergiants in the Andromeda Galaxy (M31)

TL;DR

This study identifies and analyzes red supergiants in the metal-rich galaxy M31 to test stellar evolution models and understand the impact of metallicity on mass-loss rates.

Contribution

It provides the first detailed physical properties of red supergiants in M31 using spectroscopic and photometric data, testing stellar evolution theories at high metallicity.

Findings

Identified a sample of red supergiants in M31.

Derived physical properties using MARCS atmosphere models.

Compared properties with stellar evolution models.

Abstract

Red supergiants are a short-lived stage in the evolution of moderately massive stars (10-25Mo), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass-loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of red supergiants in M31 (the most metal-rich of the Local Group galaxies) and derive their physical properties by fitting MARCS atmosphere models to moderate resolution optical spectroscopy, and from V-K photometry.