Spectroscopy of the Cataclysmic Variable UU Aquarii:s‐Waves and Bright Spots

Abstract

This paper reports the results of UV and optical spectroscopy of the nova-like variable UU Aqr. There is a decrease in the light flux of both the optical and UV emission lines at phase ~0.95. This appears to be due to an occultation of an asymmetric accretion disk. The emission-line profiles seem to show the first half of the rotational disturbance of the disk eclipse. There is a secondary eclipse at phase 0.4 in the optical continuum and the hydrogen emission lines. It is not present in the UV continuum or emission lines. This eclipse occurs when the bright spot is at superior conjunction. This raises the possibility that this is an occultation of the bright spot/s-wave region by material suspended above the central disk. The accretion disk emission in the Doppler tomogram of the Hβ emission line was used to obtain the radial velocity amplitude of the white dwarf star. The mass ratio was estimated by matching the s-wave position with stream trajectories. The results were significantly different from that of Baptista et al. These authors used the eclipse phasing of the continuum hot spot and the assumption that the hot spot is located on the stream trajectory. The reasons for this discrepancy are unclear.