Collisions Between Single Stars in Dense Clusters: Runaway Formation of a Massive Object
Abstract
Using Monte Carlo codes, we follow the collisional evolution of clusters in a variety of scenarios. We consider the conditions under which a cluster of main sequence stars may undergo rapid core collapse due to mass segregation, thus entering a phase of runaway collisions, forming a very massive star (VMS, M >= 1000 Msun) through repeated collisions between single stars. Although collisional mass loss is accounted for realistically, we find that a VMS forms even in proto-galactic nuclei models with a high velocity dispersion (many 100 km/s). Such a VMS may be a progenitor for an intermediate-mass black hole (M >= 100 Msun). In contrast, in galactic nuclei hosting a central massive black hole, collisions are found to be disruptive. The stars which are subject to collisions are progressively ground down by high-velocity collisions and a merger sequence appears impossible.
Keywords
Cite
@article{arxiv.astro-ph/0410327,
title = {Collisions Between Single Stars in Dense Clusters: Runaway Formation of a Massive Object},
author = {Marc Freitag and M. Atakan Gürkan and Frederic A. Rasio},
journal= {arXiv preprint arXiv:astro-ph/0410327},
year = {2011}
}
Comments
6 pages, 5 figures, Invited talk at "Massive Stars in Interacting Binaries" (Lac Sacacomie, Quebec, 16-20 Aug 2004)