1995/07/12 by Koji Takahashi, Takahashi, Koji · 1 citation
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9507040
19 pages, latex, 7 postscript figures, uuencoded gzipped tar file. Submitted to PASJ
arxiv created 1995/07/12 · arxiv updated 2009/12/01
The evolution of a spherical single-mass star cluster is followed in detail up to core collapse by numerically solving the orbit-averaged two-dimensional Fokker-Planck equation in energy-angular momentum space. Velocity anisotropy is allowed in the two-dimensional Fokker-Planck model. Using improved numerical codes, the evolution has been followed until the central density increased by a factor of 1014 with high numerical accuracy. The numerical results clearly show self-similar evolution of the core during the late stages of the core collapse. When Plummer's model is chosen as the initial condition, the collapse time is about 17.6 times the initial half-mass relaxation time. This is longer than the collapse time for the isotropic model by about 13%. As the result of strong relaxation in the core, the halo becomes to be dominated by radial orbits. The degree of anisotropy monotonically increases as the radius increases.