Fragmentation of elongated cylindrical clouds. VI - Comparison with observations

Hydrodynamical simulations of the collapse and fragmentation of elongated clouds are compared with observations of molecular cores, star formation regions, and binary and multiple systems. Observations of molecular clouds suggest appropriate initial conditions for numerical simulations of star formation. They include elongated structure with rotation about an arbitrary axis and low values of beta, the ratio of the absolute value of rotational to gravitational energies. The environments of young stellar objects display 'warped' disks, and 'bridges' of matter between young binaries, both of which are formed in the present simulations. The kinematics of star-forming regions is explored, and a model where large line widths are explained by the dynamical processes of infall and star formation is proposed. The formation of multiple systems is also discussed, and the observation of noncoplanarity in at least 35 percent of the multiple systems is explained in terms of the fragmentation of an elongated cloud with rotation about an arbitrary axis.