Infrared colours, distance determination and absolute magnitudes of a sample of faint cataclysmic variables

We have measured J and K colours for a sample of 36 predominantly faint cataclysmic variables (CVs) at high Galactic latitude. The J-K colours lie blueward of the main sequence, consistent with moderate (similar to 20 per cent) contamination of the secondary light by an accretion disc. We use the K magnitudes to estimate the distances of the stars. We show that most lie within about 400 pc, and only two of the stars in our sample (RU LMi and DO Lee) are convincingly at Galactic halo distances. We have determined M(v) values based on quiescent V magnitudes. The long-period dwarf nova systems (P > 3h) have absolute magnitudes which are consistent with the previously observed range, However, for the short-period dwarf novae the range of M, extends to much fainter magnitudes than previously believed (as faint as M(v) = 14). We find that those systems that have large outburst amplitudes tend to be those with the faintest M(v)s in quiescence.