V3885 Sagittarius: A Comparison With a Range of Standard Model Accretion Disks
WASHINGTON UNIV SEATTLE DEPT OF ASTRONOMY
Pagination or Media Count:
A chi-squared analysis of standard model accretion disk synthetic spectrum fits to combined Far Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph spectra of V3885 Sagittarius, on an absolute flux basis, selects a model that accurately represents the observed spectral energy distribution. Calculation of the synthetic spectrum requires the following system parameters. The cataclysmic variable secondary star period-mass relation calibrated by Knigge in 2006 and 2007 sets the secondary component mass. A mean white dwarf WD mass from the same study, which is consistent with an observationally determined mass ratio, sets the adopted WD mass of 0.7Msolar mass, and the WD radius follows from standard theoretical models. The adopted inclination, i 65 deg, is a literature consensus, and is subsequently supported by chi-squared analysis. The mass transfer rate is the remaining parameter to set the accretion disk Tsub eff profile, and the Hipparcos parallax constrains that parameter to mas transfer 5.0 - 2.0 x 10exp -9 Msolar massyrexp -1 by a comparison with observed spectra. The fit to the observed spectra adopts the contribution of a 57,000 - 5000 K WD. The model thus provides realistic constraints on mass transfer and Tsub eff for a large mass transfer system above the period gap.