SELF-SIMILAR, SELF-GRAVITATING VISCOUS DISKS

We find a self-similar steady disk solution for the gravitational pote ntials that gives equilibrium angular velocities as power-law function s of the radii, Omega proportional to R(-delta), with delta being a fr ee parameter. In particular, when a disk is totally self-gravitating i n the radial as well as perpendicular directions, we find delta = 1, l eading to a flat rotation, constant temperature, and surface density p roportional to R(-1). The disk structure is characterized by three par ameters: the viscosity parameter, alpha; the ratio of disk thickness t o radius; and the mass-flow rate. The solution shows that the nonvisco us, isothermal rotating disk modeled by Mestel can be extended to a vi scous accretion disk with a constant mass inflow.