V3885 Sagittarius: A Comparison with a Range of Standard Model Accretion Disks
Abstract
A \widetilde{χ}^2 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 0.7 M sun, and the WD radius follows from standard theoretical models. The adopted inclination, i = 65°, is a literature consensus, and is subsequently supported by \widetilde{χ}^2 analysis. The mass transfer rate is the remaining parameter to set the accretion disk T eff profile, and the Hipparcos parallax constrains that parameter to \dot{M}=(5.0± 2.0)× 10^{-9} M_{⊙} yr^{-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 \dot{M} and T eff for a large \dot{M} system above the period gap.
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.- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2009
- DOI:
- 10.1088/0004-637X/703/2/1839
- arXiv:
- arXiv:0908.1525
- Bibcode:
- 2009ApJ...703.1839L
- Keywords:
-
- novae;
- cataclysmic variables;
- stars: individual: V3885 Sagittarius;
- white dwarfs;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 41 pages, 7 figures, 9 tables. Astrophysical Journal (accepted)