High-speed photometry of the dwarf nova Z Cha in quiescence

Abstract

High-speed white light photometry of the cataclysmic variable star Z Cha is used to study the structure of the system and to derive the properties of its components. The white dwarf and bright spot eclipse timings require a mass ratio, |$q=M_\text R/M_{\text {WD}}$| of |$0.146\lt q\lt0.153$| with corresponding inclinations of 81°.9>i>>81°.6. The infalling stream passes through the light centre of the bright spot. If the central luminous object is the white dwarf its mass is 0.54±0.01 |$M_\odot$| which corresponds to a secondary star mass of 0.081±0.003 |$M_\odot$|⁠. Agreement between colour and brightness temperatures for the white dwarf and bright spot provide a rough confirmation of the 97 pc distance.