Another faint ultraviolet object associated with a globular cluster X-ray source: The case of M92

The core of the metal-poor galactic globular cluster M92 (NGC 6341) has been observed with Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope through visual, blue, and mid-UV filters in a program devoted to studying the evolved stellar population in a selected sample of galactic globular clusters. In the UV (m(255), m(255) - U) color-magnitude diagram, we have discovered a faint "UV-dominant" object. This star lies within the error box of a low-luminosity globular cluster X-ray source (LLGCX) recently found in the core of M92. The properties of the UV star discovered in M92 are very similar to those of other UV stars found in the core of some clusters (M13, 47 Tuc, M80, etc.)-all of them are brighter in the UV than in the visible and are located in the vicinity of a LLGCX. We suggest that these stars are a new subclass of cataclysmic variables.