Far-ultraviolet observations of MV Lyr.

Ultraviolet observation of MV Lyrae in the low state obtained with the IUE are presented, and their implications in establishing the nature of the system are examined. The line spectrum from 1200 to 3100 A exhibits weak absorption and emission features and is consistent with the estimated distance of 320 pc. The shape of the continuum is close to, but appreciably flatter than, a Rayleigh-Jeans distribution and is consistent with a blackbody of temperature 60,000-70,000 K. The emission can be accounted for by a hot white dwarf with a red dwarf companion, with negligible X-ray emission. Alternatively, the ultraviolet emission could be due to a hot spot, accounting also for the soft X-ray emission. In either case, the existence of a residual accretion disk is suggested by the presence of absorption features in the spectrum.