STABILITY OF A GAS-DUST DISK AT INFLECTIONS OF THE ANGULAR VELOCITY

The instability of a rotating, oblate, quasi-homogeneous system consis ting of a gas-dust mixture is analyzed. Disturbances affecting a limit ed zone and subject to self-gravitation are studied. Cases in which th e instability is the result of differential rotation are considered. A thick-disk approximation (in a cylindrical geometry) is used. The div ision of such instabilities into two types is established. The first t ype of disturbance is characterized by an azimuthal redistribution of material and an increment of the order of root G rho (G is the gravita tional constant and rho is the density). Disturbances of the second ty pe have substantially smaller increments, but occur under more general conditions, and have primarily radial density redistributions. Specif ic examples of disturbances of the second type are constructed.