The Properties of Non-Magnetic White Dwarfs in Cataclysmic Variables

Abstract

I present two recent results on the properties of the white dwarfs in non-magnetic CVs, both above and below the period gap. There is a shortage of dwarf novae with exposed white dwarfs above the gap. In response to this need, recent results on RX And are discussed. The currently known temperature distribution function of white dwarfs in dwarf novae above and below the gap is examined. The surface temperatures of the white dwarfs in the short period dwarf novae cluster closely around 15,000K with orbital periods between 1.3 and 1.5 hours. It is shown that long term compressional heating due to time-averaged accretion is the mechanism responsible for the clustering around 15,000K. The time-averaged accretion rate corresponding to this cluster of observed temperatures is almost precisely what is predicted if gravitational wave emission is driving mass transfer in dwarf novae below the period gap.