Spectroscopy of faint, high latitude cataclysmic variable candidates

Summary The fields of several variable stars believed to be cataclysmic binaries at large distances above the Galactic plane have been examined using low resolution spectroscopy in the 3600-10000 Å wavelength range. The spectral characteristics of the stars observed are presented. We find that AL Com may be an intermediate polar on the basis of its modulation period, and the observation of hydrogen lines in its spectrum. In four systems, ARCnc, DVUMa, DODra and BCUMa, there is evidence for the spectral signature of the mass-donating secondary, and we use the spectral type of the secondary to estimate the system parameters. At least two of these binaries, ARCnc and DVUMa, are eclipsing. The inferred absolute magnitude of BC UMa is faint, in the range 11.0-13.5. The blue spectrum of this star is remarkably similar to that of the unusual cataclysmic variable WZ Sge. We note that BC UMa and WZ Sge also exhibit similar, and extreme, outburst amplitudes, and have very similar orbital periods.