Star cluster in orbit around Galactic center
Animated GIF of the top view of a cluster with 65536 stars in a circular orbit around the Galactic center. The initial density profile was chosen to be a King model with W0=3 and a virial radius of 0.167pc. Stars are selected from the Scalo initial mass function between 0.3Msun and 100Msun, and initial positions and velocities of the stars are given independend of the stellar mass. The cluster rotated initially at 60\% of its break-up speed with angular momentum axis parallel to the angular momentum axis of the clusters' orbit around the Galactic center.
The cluster was born at a distance of 4pc from the Galactic center, but it spirals in due to the dynamical friction between the cluster and the background stellar population in the Galactic center. The dynamical friction terms are computed analytically and the stars which make up the Galactic background are not shown. The entire animation covers about 0.75Myr of the evolution of the cluster, one orbit around the Galactic center takes about 105 years. The crossing time in the cluster is about 12000 years.