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S. L. W. McMillan (Drexel University), S. F. Portegies Zwart (M.I.T. / University of Amsterdam)
We study the dynamical evolution of young star clusters formed within ~10 pc of the Galactic Center. Dynamical friction between a cluster and its surroundings tends to drive it toward the Galactic Center, ultimately leading to the cluster's disruption by tidal forces. During the inspiral, dynamical evolution drives the star cluster toward core collapse; the most massive stars segregate to the cluster center while lower mass stars segregate to the cluster halo. At the same time the cluster halo is stripped by the Galactic tidal field. Lower mass stars therefore tend to be lost from the cluster at larger distances from the Galactic center, while higher mass stars can reach farther in. We find a clear relation between galactocentric distance and the mean mass of stars left behind by the cluster. If the cluster goes into deep core collapse before it reaches the Galactic Center a collision runaway may occur, possibly resulting in the formation of a single object of several hundred solar masses.
We acknowledge support from NASA under grants NAG5-9264 and NAG5-10775. SPZ is a Hubble Fellow.
The author(s) of this abstract have provided an email address for comments about the abstract: steve@kepler.physics.drexel.edu