CATACLYSMIC AND CLOSE BINARIES IN STAR-CLUSTERS .3. RECOVERY OF THE QUIESCENT NOVA 1860-AD (T-SCORPII) IN THE CORE OF THE GLOBULAR-CLUSTER M80

Only two candidate classical nova eruptions have ever been seen in globular clusters. Only one, that of Nova 1860 (T Sco in M80), seems beyond any doubt a cluster member. We have obtained Hubble Space Telescope (HST) imagery of the central regions of M80 and iind a very blue candidate within 1'' of the astrometric position reported in 1860. Only one other object (of 8000) occupies a similar position in the cluster color-magnitude diagram. On the basis of position, color, and brightness we claim the first recovery of a quiescent old nova in a globular cluster core. The present luminosity of the old, quiescent nova is almost an order of magnitude less than that of most decades-old novae. This low-luminosity determination is the most accurate value known for an old nova, and consistent with the prediction of the hibernation scenario for cataclysmic binary evolution between nova eruptions. The presence of only one other blue, faint star in the core of M80 is striking and highly significant. Dozens of bright, blue cataclysmic variables should easily have been detectable in our HST images if simple tidal capture theory is correct. The extraordinary paucity of cataclysmics implies that either these binaries escape formation, are quickly destroyed or ejected from the cluster, or somehow ''hide'' by maintaining themselves in very low mass-transfer states.