SECULAR EVOLUTION OF BINARIES NEAR MASSIVE BLACK HOLES: FORMATION OF COMPACT BINARIES, MERGER/COLLISION PRODUCTS AND G2-LIKE OBJECTS

Abstract

Here we discuss the evolution of binaries around MBH in nuclear stellar\nclusters. We focus on their secular evolution due to the perturbation by the\nMBH, while simplistically accounting for their collisional evolution. Binaries\nwith highly inclined orbits in respect to their orbit around the MBH are\nstrongly affected by secular processes, which periodically change their\neccentricities and inclinations (e.g. Kozai--Lidov cycles). During periapsis\napproach, dissipative processes such as tidal friction may become highly\nefficient, and may lead to shrinkage of a binary orbit and even to its merger.\nBinaries in this environment can therefore significantly change their orbital\nevolution due to the MBH third-body perturbative effects. Such orbital\nevolution may impinge on their later stellar evolution. Here we follow the\nsecular dynamics of such binaries and its coupling to tidal evolution, as well\nas the stellar evolution of such binaries on longer time-scales. We find that\nstellar binaries in the central parts of NSCs are highly likely to evolve into\neccentric and/or short period binaries, and become strongly interacting\nbinaries either on the main sequence (at which point they may even merge), or\nthrough their later binary stellar evolution. The central parts of NSCs\ntherefore catalyze the formation and evolution of strongly interacting\nbinaries, and lead to the enhanced formation of blue stragglers, X-ray\nbinaries, gravitational wave sources and possible supernova progenitors.\nInduced mergers/collisions may also lead to the formation of G2-like cloud-like\nobjects such as the one recently observed in the Galactic center.\n