Computer simulations of gravitational encounters between pairs of binary star systems.

Encounters (collisions) between pairs of binary stars were computer simulated. The 41,564 gravitational collisions were divided into five mass families and all binaries initially had circular orbits. The exchanged energy cross section for collisions between two binaries composed of identical mass stars was found to be roughly 2-3 times that for a single star colliding with a binary having components with masses equal to that of the single star. Other results cannot be stated so easily, but the energy released by hard (low-energy) binary colisions appears to be significant. A surprising result is that roughly 40 percent of the head-on binary-binary collisions in a globular cluster core (where most of the collisions are hard ones) precipitate a physical collision between two stars, possibly leading to their coalescence.