Time dependence of the UV resonance lines in the cataclysmic variables YZ Cnc, IR Gem and V3885 Sgr

We have observed orbital variations in the ultraviolet resonance lines of YZ Cnc, IR Gem and V3885 Sgr. Optical spectroscopic observations of YZ Cnc show that the maximum absorption in the ultraviolet lines occurs |$\sim 0.7-0.8$| orbits after the transition from red to blue of the optical emission lines. IR Gem shows orbital variations in the ultraviolet lines that are as strong as those of YZ Cnc. The variations in V3885 Sgr are more moderate, and may be orbital. Lines of the Si3+, C3+ and N4+ ions vary in phase, which indicates that their regions of origin in the wind cannot be located far apart. Adding our new observations to earlier observations, we conclude that orbital variations in the ultraviolet resonance lines are common. This suggests asymmetry in the inner disc region as the cause for these variations.