Full Wilson-Devinney Analysis of Cataclysmic Variables Through the Computer Modeling of the Accretion Disks

The study of binary stars is challenging but proper use of analysis routines such as the Wilson-Devinney differential corrections program allows a reliable model of most systems to be constructed. In the case of cataclysmic variables, however, the added complexities caused by the disk of matter being accreted onto the primary star have previously prevented this type of star system from being similarly analyzed. Depending on the system, the effect of the accretion disk on the light curve can vary considerably; as a representative sample, the light curve of AR Cancri, in which the accretion disk has a prominent effect on the light curve, but does not dominate, is chosen for analysis. This will then be compared to systems in which the accretion disk plays a greater or lesser role. The cataclysmic binaries AY Piscium, AR Cancri, and DV Ursae Majoris display a variety of enigmatic and bizarre eclipse effects and light curve asymmetries due to the interaction of their accretion disks with both the subgiant and white dwarf components. Conventional light curve analysis is unable to recover basic geometrical and astrophysical parameters of these systems, or even to disentangle the light curve features due to the accretion disk from that of the underlying binary system. The approach of this work has been to develop a SPH model for the accretion disk itself, complete with relevant disk light curve normalizations that can be combined with the WD model to perform differential corrections solutions to the observed light curves of these binaries. This work describes the use of these integrated programs to determine reliable solution sets for a representative CV system. This research was supported as part of the work Henry Leckenby did for his Ph.D. at Michigan Technological University.