The population of M-type supergiants in the starburst cluster Stephenson 2

Abstract

The open cluster Stephenson 2 contains the largest collection of red supergiants known in the Galaxy, and at present is the second most massive young cluster known in the Milky Way. We have obtained multi-epoch, intermediate-resolution spectra around the CaII triplet for more than 30 red supergiants in Stephenson~2 and its surroundings. We find a clear separation between a majority of RSGs having spectral types M0-M2 and the brightest members in the NIR, which have very late spectral types and show strong evidence for heavy mass loss. The distribution of spectral types is similar to that of RSGs in other clusters, such as NGC 7419, or associations, like Per OB1. The cluster data strongly support the idea that heavy mass loss and maser emission is preferentially associated with late-M spectral types, suggesting that they represent an evolutionary phase.

Contribution to the Betelgeuse workshop, November 2012, Paris. To be published in the European Astronomical Society Publications Series, editors: Pierre Kervella, Thibaut Le Bertre & Guy Perrin

References in corpus (5)

• Discovery of an Extraordinarily Massive Cluster of Red Supergiants
• A third red supergiant rich cluster in the Scutum-Crux Arm
• Spectral Types of Red Supergiants in NGC 6822 and the Wolf-Lundmark-Melotte Galaxy
• Red supergiants around the obscured open cluster Stephenson 2
• SiO maser emission from red supergiants across the Galaxy: I. Targets in massive star clusters

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• The red supergiant population in the Perseus arm
• Clusters rich in red supergiants