Formation of the proto-sun and the evolution of the solar nebula mechanism of angular momentum transfer.

Mechanisms of angular-momentum transfer are investigated in the formation stage of the proto-sun and the evolution stage of the solar nebula. In the former stage, the angular momentum included in the initial cloud must be dissipated into interstellar gas. For this transfer, the gravitational torque, which comes from appearance of a non-axisymmetric mode (spiral mode), is found to be effective. In the stage of the evolution of the solar nebula, the gravitational torque is not so effective, because the solar nebula is not a self-gravitating system in the final stage of the evolution.