Investigating AM Her Cataclysmic Variables with OPTIMA

Abstract

We focus on short--period eclipsing binaries that belong to a class of Cataclysmic Variables (CVs). They are known as polars and intermediate polars, closely resembling their prototype AM Herculis. These binaries consist of a red dwarf and a strongly magnetic white dwarf, having orbital periods of only a few hours. Monitoring eclipses of these typically faint sources demands high-time resolution photometry. We describe the very recent results obtained for two CVs, HU Aqr and DQ Her, which were observed with the Optical Pulsar Timing Analyzer (OPTIMA). The new observations of HU Aqr confirm that the O--C (Observed minus Calculated) diagrams exhibit variations known for this binary which can be explained by a single, massive Jupiter--like planet, possibly accompanied by a very distant companion.

Proceedings of the 18th European White Dwarf Workshops -- EuroWD 12, Kraków, Poland, 13-17 August, 2012, to be published by Astronomical Society of the Pacific Conference Series (ASPCS), 4 pages, 2 figures