Session 79 - CVs and Novae.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center

## [79.16] Optical and UV Studies of the Nova-like Variable UU Aquarii

J. C. White II (Middle Tenn. State Univ.), E. M. Schlegel (CfA), R. H. Kaitchuck (Ball State Univ.), C. S. Mansperger (Allied Signal)

Like other members of its subclass, UU Aquarii is a nova-like cataclysmic variable with a story to tell. Recent spectroscopic studies of this interesting system by Haefner (1989, IBVS, 3397) and Diaz amp; Steiner (1991, AJ, 102, 1417) uncovered the white dwarf's orbital velocity using H\alpha line wings, and from this estimate the investigators inferred the white dwarf's mass. We present optical spectrophotometric data for UU Aqr collected in 1988 October and show using Doppler tomography that the system's weak disk emission is dominated by strong S"-wave emission, and hence, that previous estimates of the white dwarf's orbital velocity are unreliable. Indeed, we find a velocity semiamplitude of about 225 km s^-1 when we account for contamination from S"-wave emission, as compared to Diaz amp; Steiner's estimate of about 120 km s^-1.

In addition to our optical data, we present UV spectroscopic data for UU Aqr collected in 1994 June by the IUE spacecraft. The integrated continuum fluxes from the 22 IUE spectra show distinct periodic behavior characterized by a one-magnitude eclipse centered on primary eclipse, and we observe periodicity in line flux for the C IV \lambda\lambda1548,1550 doublet over an orbit. Though limited by the small number of low-resolution IUE spectra, we present a UV Doppler tomographic image of UU Aqr in the light of the C IV doublet. Nonaxisymmetric structure is clearly visible, hinting that something other than a boundary-layer may be responsible for the UV line emission.

J. C. W. thanks NASA and MTSU for their support through the NASA JOVE program.