Institution(s): 1. Universidad de Alicante
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 tens of thousands of solar masses. 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, at least van der Bergh-Hagen 222 is observable even in the U band, 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 providing strong hints about the possible evolutionary sequence of red supergiants. In addition, the clusters of red supergiants represent ideal tools to study metallicity in the inner regions of the Milky Way.