IUE observations of the nucleus of the galactic globular cluster NGC 2808.

Abstract

The UV spectrum of the nucleus of the galactic globular cluster NGC 2808 shows two distinct components: a point-like one, probably a supra BHB star of about 40,000K in the phase of rapid crossing of the HR diagram from the red giant tip, and a diffuse one, interpreted as a clump of blue HB stars. The contribution of these HB stars produces a cluster spectrum similar to those of the Extremely Blue HB clusters. The UV bright nature of the HB in this metal rich cluster appears related to the HB's in M13-like clusters. The implications of such an occurrence are shortly discussed.