Gravitational N-body problem and the validity of concepts of the gas model

Abstract

This paper concerns the relation between N-body systems and continuum models of stellar dynamics. A 1000-body calculation is examined for the validity of concepts used in gaseous models simulating N-body systems. Moments of velocity distribution are defined with respect to subsystems (10 shells). When moments are averaged in time and over a shell large enough, heat flows down the gradient in velocity dispersion. Redistribution of heat is a mechanism which contributes to core-collapse and core–halo formation. The coefficient of heat conductivity is in fair agreement with simple theoretical considerations.