Large Telescope Observations of the peculiar globular cluster NGC 6712 . Discovery of a UV , H α excess star in the core 1

We present results from multi-band observations in the central region of the cluster NGC6712 with the ESO Very Large Telescope. Using high resolution images we have identified three UV-excess stars. In particular two of them are within the cluster core, a few arcsec apart: the first object is star ”S” which previous studies identified as the best candidate to the optical counterpart to the luminous X-ray source detected in this cluster. The other UV object shows clearcut Hα emission and, for this reason, is an additional promising interacting binary candidate (a quiescent LMXB or a CV). The presence of two unrelated interacting binary systems a few arcsec apart in the core of this low-density cluster is somewhat surprising and supports the hypothesis that the (internal) dynamical history of the cluster and/or the (external) interaction with the Galaxy might play a fundamental role in the formation of these peculiar objects. Subject headings: globular clusters: individual (NGC6712) — stars: evolution – binaries: close