Understanding Cataclysmic Variable Accretion Disk Dynamics and Viscosity

Florida Institute Of Technology, Melbourne FL

Investigators

Abstract

AST 0205902 PI Wood The set of interacting binary star systems called cataclysmic variables serves as a marvelous laboratory to study how astrophysical accretion processes work. In that group of binaries are a number of broad categories of objects, each category further divided into classes of objects of different outburst and quiescence behaviors. Significant amounts of observational effort has been expended in an attempt to understand the underlying accretion physics in these systems Now once seemingly intractable computational problems are accessible via better algorithms and desktop supercomputing with 3-dimensional hydrodynamic codes, and progress has been made. This project will advance efforts to model a particular, and for a long-while puzzling, phenomenon observed in SU Ursa Majoris-type systems: so-called superhumps observed during especially bright outbursts. The PI has successfully modeled approximate superhump behavior using his smoothed particle hydrodynamic code in a fully 3-dimensional mode. The superhumps in light curves are true instabilities of tilted accretion disks. This project will expand the work by adding disk viscosity due to magnetic fields and creating a grid of light curves and modeled disks that will be delivered to the astronomy community as an atlas. ***