Accretion Model for Outbursts of Dwarf Nova

Abstract

Structure and stability of an accretion ring around the white dwarf component of a dwarf nova is investigated on the basis of the theory of accretion disks. It is found that the surface density of the accretion ring increases to a certain critical value by continual mass transfer from the red star companion, at which thermal instability develops within the accretion ring and the material of the ring drifts inward to produce a luminous accretion disk around the white dwarf. The theory developed here is in good agreement with observational requirements of dwarf nova.