Effects of Hardness of Primordial Binaries on Evolution of Star Clusters

Ataru Tanikawa, Toshiyuki Fukushige

Published 2010-05-13Version 1

We investigate effects of hardness of primordial binaries on whole evolution of star clusters by means of N-body simulations. Using newly developed code, GORILLA, we simulated eleven N=16384 clusters with primordial binaries whose binding energies are equal in each cluster in range of 1-300kT_0, where 1.5kT_0 is average stellar kinetic energy at the initial time. We found that, in both soft (< 3kT_0) and hard (> 300kT_0) limits, clusters experience deep core collapse. In the intermediate hardness (10-100kT_0), the core collapses halt halfway due to an energy releases of the primordial binaries. The core radii at the halt can be explained by their energy