A survey of Helium accreting white dwarfs

We propose to carry out a survey of AM CVn systems close binaries in which awhite dwarf is accreting material from a white dwarf or semidegenerate heliumstar. We propose to obtain simultaneous Xray and UV data with high timeresolution. By correlating their light curves we will be able to test discinstability models for Helium dominated discs. These discs are expected to havedifferent properties from Hydrogen dominated discs. The source of Xray emissionin these systems is not known. These observations will conclusively answer thisquestion. We will also search for emission lines in the Xray spectra this willallow us to determine the chemical compostion of these systems and hence theirevolutionary history. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]