Star Formation: 3D Collapse of Turbulent Cloud Cores

We have performed fully 3D simulations of the collapse of molecular cloud cores which obey the logatropic equation of state. By following the collapse of these cores from states of near hydrodynamic equilibrium, we are able to produce accretion histories which closely resemble those of observed cores. The accretion proceeds in four distinct stages: an initial period of very slow accretion; a period of vigorous accretion following the development of a central density singularity, with a mass accretion rate proportional to t^3, as predicted by self-similar models; a period of relatively stable, vigorous accretion; and finally a gradual decrease in the accretion rate once about 50% of the available mass of the molecular cloud core has been accreted. These results may explain the accretion histories of cores as they pass through the pre-protostellar, Class 0, and Class I stages.