The early evolution of star clusters in compressive and extensive tidal fields

Abstract

We present N-body simulations of star clusters that initially evolve within a strong compressive tidal field and then transition into an extensive tidal fields of varying strengths. While subject to compressive tides, clusters can undergo significant heating due to two-body interactions and mass-loss due to the stellar evolution. When the cluster transitions into an extensive tidal field it is supervirialized, which leads to a rapid expansion and significant mass-loss before the cluster reaches virial equilibrium. After the transition, clusters are significantly less massive, more extended and therefore more tidally filling than clusters that have spent their entire lifetimes in a similar extensive tidal field.