Physical Properties of Red Supergiants

TL;DR

This study refines the understanding of red supergiants' physical properties using advanced models, aligning observations with evolutionary theories and highlighting their potential role in galactic dust production.

Contribution

It provides new effective temperatures and luminosities for RSGs across different galaxies, improving agreement with stellar evolution models and exploring dust contributions.

Findings

Better agreement between observed RSG properties and models.

Evidence of circumstellar dust affecting observations.

RSGs may be significant dust sources in certain galaxies.

Abstract

Red supergiants (RSGs) are an evolved stage in the life of intermediate massive stars (<25Mo). For many years their location in the H-R diagram was at variance with the evolutionary models. Using the MARCS stellar atmosphere models, we have determined new effective temperatures and bolometric luminosities for RSGs in the Milky Way, LMC, and SMC, and our work has resulted in much better agreement with the evolutionary models. We have also found evidence of significant visual extinction due to circumstellar dust. Although in the Milky Way the RSGs contribute only a small fraction (<1%) of the dust to the interstellar medium (ISM), in starburst galaxies or galaxies at large look-back times, we expect that RSGs may be the main dust source. We are in the process of extending this work now to RSGs of higher and lower metallicities using the galaxies M31 and WLM.