N-body models of rotating globular clusters

In this paper we examine the dynamical evolution of rotating globular clusters with direct N-body models. Our initial models are rotating King models, and we obtain results both for equal-mass systems and for systems composed of two mass components. Previous investigations using a Fokker-Planck solver have shown that rotation has a noticeable influence on stellar systems such as globular clusters that evolve by two-body relaxation. In particular, it accelerates their dynamical evolution through the gravogyro instability. We have validated the occurrence of the gravogyro instability with direct N-body models. In the case of systems composed of two mass components, mass segregation takes place, a process that competes with the rotation in the acceleration of the core collapse. The 'accelerating' effect of rotation was detected in our isolated two-mass N-body models. Finally, we look at rotating N-body models in a tidal field within the tidal approximation. It turns out that rotation increases the escape rate significantly. A difference between retrograde- and prograde-rotating stellar clusters, with respect to the orbit of the cluster around the Galaxy, occurs. This difference is the result of the presence of a 'third integral' and chaotic scattering, respectively.