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We propose that the cloud moving on a highly eccentric orbit near the centralblack hole in our Galaxy, reported by Gillessen et al., is formed by aphotoevaporation wind originating in a disk around a star that is tidallyperturbed and shocked at every peribothron passage. The disk is proposed tohave formed when a stellar black hole flew by the star, tidally disrupted itsenvelope, and placed the star on its present orbit with some of the tidaldebris forming a disk. A disrupting encounter at the location of the observedcloud is most likely to be caused by a stellar black hole because of theexpected dynamical mass segregation; the rate of these disk-forming encountersmay be as high as $\sim 10^{-6}$ per year. The star should also be spun up bythe encounter, so the disk may subsequently expand by absorbing angularmomentum from the star. Once the disk expands up to the tidal truncationradius, the tidal perturbation of the outer disk edge at every peribothron mayplace gas streams on larger orbits which can give rise to a photoevaporationwind that forms the cloud at every orbit. This model predicts that, after thecloud is disrupted at the next peribothron passage in 2013, a smallerunresolved cloud will gradually grow around the star on the same present orbit.An increased infrared luminosity from the disk may also be detectable when theperibothron is reached. We also note that this model revives the encountertheory for planet formation.

A star disrupted by a stellar black hole as the origin of the cloud falling toward the Galactic center