On the Optical Pulsations in DQ Her Stars

Abstract

DQ Her stars are cataclysmic binary systems in which matter from a late-type near-main sequence star is accreted onto an asynchronously spinning magnetized white dwarf. X-rays generated at shocks at the magnetic poles of the white dwarf sweep the system with a “lighthouse” beam, producing optical signals modulated at the spin period of the white dwarf and/or at one or more spin-orbit sidebands. The shape of the pulse amplitude spectrum yields information about the emission mechanism of the pulsed component of the light. [See de Martino et al. in these proceedings.]