Binary Disruption by Massive Black Holes in Globular Clusters

Abstract

A massive (~102-104 M☉) black hole at the center of a globular cluster will tidally disrupt binaries that pass sufficiently close. Such an encounter results in the capture of one binary component by the black hole and ejection of the other star. A 103 M☉ black hole disrupts one binary every 1-10 Myr; captured stars orbit with initial periods of days to decades. Although 100 stars are captured in only 1 Gyr, the number with periods of <10 yr at any one time is probably less than 10, regulated by stellar interactions and tidal disruption by the black hole. Binary disruption and stellar capture should be critically examined with detailed numerical simulations, in order to corroborate the analytic results given here and to weigh possible observational consequences.