Clusters rich in red supergiants

Abstract

In the past few years, several clusters containing large numbers of red supergiants have been discovered. These clusters are amongst the most massive young clusters known in the Milky Way, with stellar masses reaching a few $10^4$M${}_{\odot }$. They have provided us, for the first time, with large homogeneous samples of red supergiants of a given age. These large populations make them, despite heavy extinction along their sightlines, powerful laboratories to understand the evolutionary status of red supergiants. While some of the clusters, such as the eponymous RSGC1, are so obscured that their members are only observable in the near-IR, some of them are easily accessible, allowing for an excellent characterisation of cluster and stellar properties. The information gleaned so far from these clusters gives strong support to the idea that late-M type supergiants represent a separate class, characterised by very heavy mass loss. It also shows that the spectral-type distribution of red supergiants in the Milky Way is very strongly peaked towards M1, while suggesting a correlation between spectral type and evolutionary stage.

Summary of invited talk presented at the IAU XXIX General Assembly (Honolulu, 2015) in Focus Meeting 16 (Stellar Behemoths - Red Supergiants across the local Universe, conveyed by Ben Davies). V2 corrects a typo in the reference list

References in corpus (9)

• A massive cluster of Red Supergiants at the base of the Scutum-Crux arm
• The cool supergiant population of the massive young star cluster RSGC1
• A third red supergiant rich cluster in the Scutum-Crux Arm
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• A third cluster of red supergiants in the vicinity of the massive cluster RSGC3
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• VdBH 222: a starburst cluster in the inner Milky Way
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Cited by in corpus (1)

• Berkeley 51, a young open cluster with four yellow supergiants