Did the binary stars in globular clusters come to an early end by being too eccentric?

Abstract

The orbits of hard binaries in globular clusters shrink and develop high eccentricities in encounters with other stars. The most eccentric binaries suffer the physical coalescence of their two components. Slightly less eccentric binaries shrink down to very tightly bound binaries as a result of dissipation (tidal, gravitational radiation) at periastron. Visual binaries in dense globular clusters have either been dissociated by stellar encounters or they have shrunk by these mechanisms to form a combination of coalesced stars and very close binaries. These mechanisms may contribute significantly to the observed scarcity of binaries among globular cluster giants, but at the same time, they form and allow the retention of the close binaries that are needed to produce the x-ray sources in globular clusters.