HP-1 - A BLUE HORIZONTAL-BRANCH GLOBULAR-CLUSTER IN THE BULGE

We present V, I colour-magnitude diagrams of the globular cluster HP 1 obtained at the European Southern Observatory New Technology Telescop e under exceptional seeing conditions. The cluster shows blue horizont al branch (HE) and red giant branch morphologies very similar to clust ers of intermediate metallicity such as NGC 6752; we therefore estimat e [Fe/H] approximate to -1.5 for HP 1. The blue HE morphology is exten ded, which is not unusual for a post-core-collapse cluster. We derive a reddening of E (B - V) = 1.19 and a distance d. = 6.85 kpc. HP 1 mig ht be a halo cluster crossing the bulge or belong to the low-metallici ty tail of the bulge.