Studies of Cataclysmic Variables.

Abstract

A number of separate studies of cataclysmic variable stars are presented. We begin with a discussion of 3 color simultaneous photometry of the AM Herculis-type binary 2A0311-227. Light curves, and B-V and U-B color curves are shown. A Fourier analysis has failed to detect the 6-minute quasi-periodic oscillation found earlier in optical photometry and x-ray observations. It has detected oscillations at 13.7 and 20.2 minutes which are interpreted in terms of a non-sinusoidal light curve. The average orbital motion of the system in the color-color plane is shown. We next consider radial velocity studies of the emission lines in 5 systems. These are 2A0311-227, H2252-035, YY DRA, BT MON, and SW UMA. For 2A0311-227 we have performed numerical models of mass transfer from the secondary, along the magnetic field lines, to try and match the observed velocity curve. We find that this model specifies the orientation of the dipole uniquely. The system BT mon was found to have different velocity curve semiamplitudes and phases for H and He II. These observations are discussed in terms of streaming motion in the accretion disk. SW UMA is a dwarf nova whose orbital period has yet to be determined. By looking for small periodic changes in the H alpha line wing we find a possible periodicity at 1.25 hours. A spectroscopic survey of 69 cataclysmic variables is presented. Accurate coordinates, representative spectra, and finding charts for all objects are given. In addition, line fluxes, equivalent widths, and line widths are given for all of the emission lines in 153 spectra. These data are then analyzed to look for corrrelations between spectrum variables and between spectrum and system variables. The results are discussed in terms of line emission from accretion disks. In an effort to make optical identifications for unidentified x-ray sources objective prism Schmidt plates were obtained. These were searched and the results are presented.