CE - 315 : A New Interacting Double - degenerate Binary Star

We present spectroscopic observations of object CE-315 revealing a blue continuum with strong emission lines. Most of the detected lines are identified with He I or He II in emission with a handful of faint lines of nitrogen. Notable is the complete absence of hydrogen lines. The He lines exhibit triple-peaked profiles with remarkably broad widths, of ∼2000 km s (FWZP). The observations show that CE-315 is an interacting binary system with an orbital period of 65.1±0.7 minutes, and a mass ratio of 0.022. We conclude that the most likely scenario for this object is that of an accreting ∼0.77M⊙ white dwarf with a ∼0.017 M⊙ helium white dwarf as mass donor. Subject headings: Stars: binaries — stars: white dwarfs — stars: cataclysmic — stars: individual (CE-315)