Cross sections for tidal capture binary formation and stellar merger

The cross sections for tidal capture binary formation are computed for polytropic models with indices n = 3/2, 2, and 3 to represent a wide range of stellar models. The computational procedure for the tidal capture cross sections is summarized, and the results of normal mode analyses and the capture cross sections are presented. It is estimated that 25 percent of the tidally captured binaries become mergers for a stellar system whose rms velocity is roughly 10 km/s (typical for globular clusters), while about 50 percent are expected to become mergers for rms velocity of roughly 300 km/s (typical for galactic nuclei). The implications of these results for the dynamical evolution of stellar systems influenced by tidally captured binaries are briefly discussed.