V471 TAU - ECLIPSING LABORATORY FOR WIND ACCRETION AND STELLAR ACTIVITY STUDIES

We plan to observe V471 Tau,an eclipsing 12.5h period precontact cataclysmicbinary in order to study evidence for accretion via stellar wind from the activeK2V secondary. HST UV spectra have established that the white dwarf surfaceshows inhomogenities of silicon, which could be due to magnetically funnelledaccretion In this programme we plan to study the spin phase resolved Xrayspectrum of the WD together with simultaneous Xray & UV spin lightcurves inorder to model the variation and thus check the stellar wind accretionhypothesis. The eclipsing nature of the system allows us to fully separate Xrayemission from the WD and the K star. This enables us to model emission from eachsource separately and provides extra constraints on the location of the WD magnetic poles. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]