Evolution of rotating interstellar clouds. III - On the formation of multiple star systems

The evolution of a rotating massive cloud, starting at interstellar densities, continuing through a series of intermediate fragmentation stages, and ending with stellar multiple systems with components near the main sequence, is outlined. The scenario is based on results of two- and three-dimensional numerical hydrodynamical calculations of collapsing clouds. Transfer of spin angular momentum primarily into orbital motion is assumed to occur at each fragmentation stage. Expected initial conditions in the cloud lead to final fragments which have in many cases the masses and angular momenta appropriate to observed main-sequence systems. Other points of comparison with observations are briefly noted.