Jongsuk Hong (Seoul Natl. Univ.): N-body and Fokker-Planck simulations of rotating star clusters with 2-component mass spectrum

Fri, Nov. 19, 2010, 3:00 p.m. (KIAA Seminar Room)

To understand the effect of the initial rotation for tidally bound clusters with mass spectrum, we performed both N-body and Fokker-Planck simulations for two-component clusters with different degrees of initial rotation. We confirmed that the cluster evolution is accelerated by the initial rotation as well as the mass spectrum. For the slowly rotating models, the time evolution of mass, energy and angular momentum show good agreements between N-body and Fokker-Planck calculations. On the other hand, for the rapidly rotating models, there are significant differences between two approaches at the early stage of the evolution. By investigating cluster shapes, we concluded that these differences are mainly due to rotational instability that takes place for very rapidly rotating clusters. The shape of cluster for N-body simulations becomes tri-axial or even prolate, while the 2-dimensional Fokker-Planck simulation can treat only oblate type axisymmetric systems.