UIT DETECTION OF HOT STARS IN THE GLOBULAR CLUSTER NGC 362

摘要

We used the Ultraviolet Imaging Telescope during the 1995 March Astro-2 mission to obtain a deep far-UV image of the globular cluster NGC 362, which was formerly thought to have an almost entirely red horizontal branch (HB). Eighty-four hot (T_(eff) > 8500 K) stars were detected within a radius of 8.25′ of the cluster center. Of these, 43 have FUV magnitudes consistent with HB stars in NGC 362 and at least 34 are cluster members. The number of cluster members is made uncertain by background contamination from blue stars in the Small Magellanic Cloud (SMC). There are six candidate supra-HB stars that have probably evolved from the HB. We discuss the implications of these results for the production of hot blue stars in stellar populations.