Hydrodynamical Simulations of the Non-Ideal Gravitational Collapse of a Molecular Gas Cloud

Abstract

In this paper we present the results of a set of numerical simulations aimed to study the gravitational collapse of a spherically symmetric, rigidly rotating, isolated, interstellar gas cloud. To account for the thermodynamics of the gas we use a barotropic equation of state (beos for brevity) that depends on the density ρ of the cloud and includes a critical density as a free parameter, ρcrit. During the early collapse, when ρ << ρ-crit, the beos behaves as an ideal gas equation of state. For the late collapse, when ρ ≥ ρ-crit, the beos includes an additional term that accounts for the heating of the gas due to gravitational contraction. We investigate the occurrence of prompt fragmentation of the cloud for which we use four dierent values of ρ-crit. We work with two kinds of collapse models, according to the initial radial density profile: the uniform and the Gaussian clouds.