Dynamics of accretion shocks in AM Herculis systems: Models for high mass white dwarfs

Abstract

Several AM Her objects show low amplitude, 1 Hz quasi‐periodic oscillations in power spectra of their optical emission. Wolff, Wood, and Imamura, in a recent series of papers, show that accretion noise driven radiative shocks are a plausible model for this phenomenon. Here, we discuss how two‐temperature effects can play an important role in regulating the frequency of the shock oscillations within the formalism outlined by Wolff et al. We argue that two‐temperature effects can be important in accretion flows onto white dwarfs with masses as low as 0.6 M⊙ if cyclotron radiation is an important energy loss process in the shocked gas. The planned USA x‐ray timing experiment on the ARGOS satellite should be able to detect the quasi‐periodic x‐ray oscillations predicted by our shock oscillation model.