Extreme Be stars in the Magellanic Clouds.

Abstract

In the course of a spectroscopic investigation of the O-type stars in the Magellanic Clouds, a population of luminous Be stars was serendipitously encountered. They are here referred to as extreme Be stars, following the terminology used by Schild (1966) for a population of Be stars in the region of h and Chi Persei which lie significantly above the main sequence. As members of the Clouds, their luminosities and intrinsic colors can be determined directly. A comparison of these new high-luminosity Be stars with known H-beta-emission-line supergiants in the Clouds is made in both the optical and UV spectral regions. The Galactic counterparts of these Be stars are also discussed. Although these Be stars are an average of several magnitudes brighter than those in the Galaxy, this may in part be a selection effect.