FRAGMENTATION OF MOLECULAR CLOUDS - THE INITIAL PHASE OF A STELLAR CLUSTER

The isothermal gravitational collapse and fragmentation of a region wi thin a molecular cloud and the subsequent formation of a protostellar cluster are investigated numerically. The clump mass spectrum that for ms during the fragmentation phase can be well approximated by a power- law distribution dN/dM proportional to M-1.5. In contrast, the mass sp ectrum of protostellar cores that form in the centers of Jeans-unstabl e clumps and that evolve through accretion and N-body interactions is described by a lognormal distribution with a width that is in excellen t agreement with observations of multiple stellar systems.