We have obtained the first far-ultraviolet spectrum of the nova-like cataclysmic variable MV Lyrae using the Far Ultraviolet Spectroscopic Explorer (FUSE). We also obtained contemporaneous optical light curves and spectra. All data are from a deep faint accretion state of MV Lyr. We constructed a model for the system using the BINSYN software package; results from this model include the following: (1) The white dwarf has T eA ¼ 47; 000 K, photospheric log g ¼ 8:25, and metallicity of Z % 0:3 Z . (2) The secondary star is cooler than 3500 K; it contributes nothing to the far-ultraviolet flux and a varying amount to the optical flux (from 10% at 5200 Å to 60% at 7800 Å ). (3) The accretion disk, if present at all, contributes negligibly to the spectrum of MV Lyr. Irradiation considerations imply that the mass transfer rate is no more than 3 Â 10 À13 M yr À1 .(4) Assuming no disk is present, the model optical light curve has an amplitude approximately 50% larger than that of the sinusoidal modulation (on the orbital period) in the observed optical light curve, suggesting that the secondary star might be shaded by a nascent disk and/or have starspots near the L1 point. (5) The scaling of the model spectrum to the observed data leads to a distance of d ¼ 505 AE 50 pc to MV Lyr.

We use analysis results from a low state of the VY Sculptoris system MV Lyrae, considered in an earlier paper (Hoard et al., 2004, ApJ, 604, 346), to study archival IUE spectra taken during an intermediate state and a HST spectrum taken during a high state. The intermediate state spectrum can be best fit by an isothermal accretion disk extending half way to the tidal cutoff radius. The high state spectrum can be best fit by a standard model extending from an inner truncation radius to an intermediate radius and an isothermal accretion disk beyond.Comment: 37 pages, 11 Postscript figures, 2 table

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