Random gravitational encounters and the evolution of spherical systems. VIII - Clusters with an initial distribution of binaries

The effects of an initial binary population on the evolution of an isolated globular cluster are investigated by Monte Carlo techniques. In all models, the central regions develop a marked concentration of binaries as a result of mass stratification; in the innermost core, binaries ultimately predominate and react more with each other than with single stars. For the models considered, 42-92% of the binary energy released goes into reaction products which escape from the cluster, the percentage increasing with binary hardness. The energy imparted to the remaining cluster maintains the expansion of the system and postpones the collapse of the core. For most models, this collapse finally occurs, perhaps in part because most of the energy released is transmitted to stars outside the collapsing core in which the reactions take place. Up to 30% of the binaries present initially have been dissociated by the time of core collapse.