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Paper: Collisions Between Single Stars in Dense Clusters: Runaway Formation of a Massive Object
Volume: 367, Massive Stars in Interactive Binaries
Page: 707
Authors: Freitag, M.; Guerkan, M.A.; Rasio, F.A.
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* > 1000M) 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 kms−1). Such a VMS may be a progenitor for an intermediate-mass black hole (M ≥ 100M). 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.
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