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[44.12] The Accretion Rate and Temperature of the Accreting White dwarf in the Dwarf Nova SS Cygni During Quiescence

M. V. Lesniak, E. M. Sion (Villanova U.)

Using the the newly determined parallax for the dwarf nova SS Cygni, we have analyzed IUE archival spectra of the system during quiescence. The spectra are fit poorly by optically thick accretion disk models alone. The best-fitting composite white dwarf plus accretion disk models to the most representative quiescent spectra yield T_eff = 35,000K ± 1000K, \dot{M} = 5\times 10^-11 M_\odot/yr, i = 41^o, with a scale factor-derived distance of 166\,pc, in excellent agreement with the distance of 166\,pc from the trigonometric parallax. During quiescence, the accretion disk dominates the FUV flux. In contrast with quiescence, a best-fitting steady state disk model to a typical outburst spectrum yielded an accretion rate of 4\times 10^-9 M_\odot/yr and a scale factor-derived distance of 162\,pc, in close agreement with the parallax distance. During outburst the accretion disk provides essentially all of the FUV flux.

This work was supported by NASA grant NAG5-11182 to Villanova University and by a summer undergraduate research grant from the Delaware Space Grant Consortium.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.