Binaries as a heat source in stellar dynamics - Release of binding energy

The present numerical scattering experiment results confirm and make more specific previous analytic approximations of the role played by binaries in the energy budget of dense stellar systems, showing that soft binaries become softer while hard binaries become harder. The average amount of energy exchange is plotted as a function of incoming star velocity for an initial binary eccentricity of 0.7. The energy exchange curve forms a smooth function, changing sign in a narrow transition region around the watershed velocity, approaching asymptotic values at either side. These results can serve as input models of evolving star systems, in a manner similar to that of nuclear cross sections in models of stellar evolution.