THE FATE OF STAR CLUSTERS NEAR THE GALACTIC CENTER. Ⅰ. ANALYTIC CONSIDERATIONS

摘要

A star cluster in a galactic nucleus sinks toward the galactic center because of dynamical friction. As it spirals inward, the cluster loses mass through stellar evolution, relaxation driven evaporation, and tidal stripping, eventually dissolving in the galactic tidal field. We model the in-spiral of dense young star clusters near the center of our Galaxy to study the extent of the region of parameter space in which the cluster can reach the inner parsec of the Galaxy within a few million years. Since we neglect changes in cluster structure due to internal evolution, the present study is most applicable to star clusters less than about one initial relaxation time old. We find that only star clusters with initial masses approx> 10~5 solar mass can reach the Galactic center from an initial distance of approx> 60 pc within one initial relaxation time or a few million years, whichever is smaller.