title: Formation and Self-Gravitational Evolution of Protoplanetary Disks

authors: Sanemichi Takahashi, Shu-ichiro Inutsuka, and Masahiro N. Machida

abstract: We investigate the formation process of self-gravitating protoplanetary disks. The angular momentum in the disk is redistributed by the action of gravitational torque in the massive disk in its early formation stage.  We develop a simplified one-dimensional accretion disk models that take into account the infalling gas from the envelope onto the disk and the transfer of angular momentum within the disk in terms of effective viscosity.  We find characteristic property in the evolution that does not depend on the detail of modeling for effective viscosity.  The resultant disks have structures that are in agreement with the results of three dimensional simulations. Out model will be a useful tool for further modeling of chemistry, radiative transfer and planet formation in the protoplanetary disks.