Evaporation of Stars from Isolated Clusters.

The rate of evaporation from a spherical cluster is recomputed from the full Fokker-Planck equation for the velocity-distribution function. The one essential idealization is that the gravitational potential of the cluster is taken to be constant inside a sphere of radius R and to be zero outside. Computations are made for stars of different masses to yield the evaporation time, t , as a function of mass, m. If stars of average mass, m , predominate, then for each decrease of rn/mo by 0.2, the evaporation time decreases by a factor of 2. The radial distribution of stars in an isolated cluster is also discussed.