Red Supergiants in the Local Group

Abstract

Galaxies in the Local Group span a factor of 15 in metallicity, ranging from the super-solar M31 to the Wolf-Lundmark-Melotte (WLM) galaxy, which is the lowest-metallicity (0.1xZsun) Local Group galaxy currently forming stars. Studies of massive star populations across this broad range of environments have revealed important metallicity-dependent evolutionary trends, allowing us to test the accuracy of stellar evolutionary tracks at these metallicities for the first time. The RSG population is particularly valuable as a key mass-losing phase of moderately massive stars and a source of core-collapse supernova progenitors. By reviewing recent work on the RSG populations in the Local Group, we are able to quantify limits on these stars' effective temperatures and masses and probe the relationship between RSG mass loss behaviors and host environments. Extragalactic surveys of RSGs have also revealed several unusual RSGs that display signs of unusual spectral variability and dust production, traits that may potentially also correlate with the stars' host environments. I will present some of the latest work that has progressed our understanding of RSGs in the Local Group, and consider the many new questions posed by our ever-evolving picture of these stars.

9 pages, 1 figure; to appear in proceedings of the Betelgeuse 2012 Workshop

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Cited by in corpus (5)

• A new survey of cool supergiants in the Magellanic Clouds
• Massive Stars in the Galaxies of the Local Group
• Spectral type, temperature and evolutionary stage in cool supergiants
• Evolved Massive Stars at Low-metallicity II. Red Supergiant Stars in the Small Magellanic Cloud
• Identification of dusty massive stars in star-forming dwarf irregular galaxies in the Local Group with mid-IR photometry