The Anomalous Accretion Disk of the Cataclysmic Variable RW Sextantis

Synthetic spectra covering the wavelength range 900-3000 Å provide an accurate fit, established by a χ² _ν analysis, to a combined observed spectrum of RW Sextantis. Two separately calibrated distances to the system establish the synthetic spectrum comparison on an absolute flux basis but with two alternative scaling factors, requiring alternative values of \dot{M} for final models. Based on comparisons for a range of \dot{M} values, the observed spectrum does not follow the standard model. Rather than the exponent 0.25 in the expression for the radial temperature profile, a value close to 0.125 produces a synthetic spectrum with an accurate fit to the combined spectrum. A study of time-series Far Ultraviolet Spectroscopic Explorer spectra shows that a proposed warped or tilted disk is not supported by the data; an alternative proposal is that an observed non-axisymmetric wind results from an interaction with the mass transfer stream debris.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-26555, and the NASA-CNES-CSA Far Ultraviolet Explorer, which is operated for NASA by the Johns Hopkins University under NASA contract NAS5-32985.