The influence of dynamical relaxation and tidal shocking on the evolution of star clusters

We report results of collisional N-body calculations, aimed to study the evolution of star clusters moving on elliptic orbits through their parent galaxies. Our clusters consist of equal-mass stars and their initial density distributions are given by King-profiles. The tidal radii of the King-profiles are adjusted such that they match the tidal radii of the clusters at perigalacticon. We study the mass-loss of the clusters under the influence of two destruction mechanisms: relaxation due to two body encounters; and tidal heating/tidal stripping due to successive pericenter passages. Tidal effects play a role in the initial phases, but their influence decreases since stars that are most influenced by the tidal field are quickly lost from the clusters. We conclude that relaxation is the dominant escape mechanism for compact clusters which do not extend their perigalactic tidal radii.