Multiple fragmentation models of centrally condensed molecular cloud cores

The protostellar collapse of centrally condensed, rapidly rotating (beta approximate to 0.17) cores, along with implicitly assumed m=2 density variations-as appropriate for prolate-like shapes-is investigated for initial configurations with power-law distributions (rho proportional to r(-n) with n > 1) and internal non-rotational motions. The central condensation and irrotational velocity field assumed for the initial models are consistent with the cloud structure that results in the early spherically symmetric collapse of an initially uniform-density static sphere, The results imply that multiple protostellar systems may form in the dynamical collapse of strongly centrally condensed, differentially rotating prolate-like core models through intermediate stages first involving the formation of a stable binary system. The binary components that form have elongated shapes and are seen to subfragment in the further evolution leading to the formation of fragmented filamentary structures, As long as uniform rotation is included in the initial conditions, rapid central collapse forces the initial m=2 instability to decay into a dense prolate core which then fragments along its major axis into small-scale condensations, Centrally condensed cores of non-prolate shape may still generate multiple systems during their isothermal collapse, but without the formation of filaments.