Аннотация:Two-dimensional models for the motion of asymptotically thin, plane gas disks are developed in the framework of classical mechanics. The models are based on the averaging of the transverse coordinate in the basis variational equation for the adiabatic motion of an ideal gas. Equations of motion of the disk in its proper gravitational field and in the gravitational field of a specified material point are obtained along with necessary boundary and discontinuity equations.