Tidal Capture Formation of Binary Systems and X-ray Sources in Globular Clusters

Abstract

It is proposed that X-ray sources associated with globular star clusters may be very close binary systems resulting from tidally dissipative two-body encounters between ordinary stars and compact objects in the dense cluster cores. The capture process resulting in such systems is analyzed, and the X-ray emission from them is estimated. It is shown that this process can only form very close binary systems, pairs of ordinary stars can form close binary systems in this way, the chance of a genuine collision between a compact object and an ordinary star is not negligible, and collisions between pairs of ordinary stars may be relevant to the 'blue straggler' phenomenon.