Constraining the Mass Loss Geometry of Beta Lyrae

Massive binary stars lose mass by two mechanisms: jet-driven mass loss during periods of active mass transfer and by\udwind-driven mass loss. Beta Lyrae is an eclipsing, semi-detached binary whose state of active mass transfer provides a\udunique opportunity to study how the evolution of binary systems is affected by jet-driven mass loss. Roche lobe overflow\udfrom the primary star feeds the thick accretion disk which almost completely obscures the mass-gaining star. A hot spot\udpredicted to be on the edge of the accretion disk may be the source of beta Lyrae’s bipolar outflows. I present results\udfrom spectropolarimetric data taken with the University of Wisconsin’s Half-Wave Spectropolarimeter and the Flower\udand Cook Observatory’s photoelastic modulating polarimeter instrument which have implications for our current understanding\udof the system’s disk geometry. Using broadband polarimetric analysis, I derive new information about the\udstructure of the disk and the presence and location of a hot spot. These results place constraints on the geometrical distribution\udof material in beta Lyrae and can help quantify the amount of mass lost from massive interacting binary systems\udduring phases of mass transfer and jet-driven mass loss