Relaxation of Star Clusters and Color Gradients

Abstract

Large interstellar distances imply that protostars are dynamically decoupled from gas ram pressure (see, e.g., Aarseth, Lin & Papaloizou 1988) and are effectively isolated self-gravitating objects. With this in mind we apply Newtonian gravity to collapsing cold spheroids of point masses to model the Lin-Mestel-Shu (1965) solution for dust. Incomplete violent relaxation (e.g., van Albada 1982) means that traces of the initial orbit distribution in energy remain. We show here that furthermore the degree of orbit mixing achieved correlates well with initial morphology, by collapsing two-mass component uniform spheroids of different aspect ratio. We setup a test problem to seek out a relation between orbit survival and initial morphology which we then solve numerically.