Z Camelopardalis: Outburst P Cygni Profiles and Quiescent Continuum

Abstract

The authors present the first orbital study of the C IV P Cygni profile in the dwarf nova Z Cam, a system of intermediate inclination. A modulation of the absorption equivalent width is apparent, with phases suggesting an effect from the mass-transfer stream. Over the outburst cycle, the strength of the P Cygni absorption and emission components is greater after outburst than during the standstill configuration, while the terminal velocities and central absorption wavelength are similar. The continuum flux distributions during standstill and decline are similar, consistent with an α = -2.0 power law, while the quiescent-state UV flux distribution can be separated into two components. The best fits are a 14,000K blackbody and an α = -3.6 power law, conceivably representing contributions from the hot spot and the inner disk/boundary layer.