Goddard High-Resolution Spectrograph Observations of the Interacting Binary System W Serpentis
Rosenblatt, E. I.; Shore, S. N.; Weiland, J. L.; Lyons, R. W.; Beaver, E. A.
Abstract
Spectroscopic observations of the interacting binary system W Serpentis have been made at two orbital phases using the Goddard High-Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST). Differences in Si IV t393, 1403λλ emission-line strengths and profile shapes observed between the two phases suggest that a hot spot exists where the giant stellar companion has transferred mass to an accretion disk surrounding the mass-gaining component. Moreover, strong absorption features superposed on the Si IV emission lines indicate that the accretion disk is geometrically and optically thick. These absorption features have been modeled to constrain the physical conditions of the disk.