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J. Lake (Eastern Coll.), E. M. Sion (Villanova Un.)
UZ Serpentis and SS Aurigae are both U Geminorum-type dwarf novae with similar orbital periods, outburst amplitudes, and outburst recurrence times. Since dwarf novae above the period gap have higher accretion rates, their accretion disks may remain optically thick even during quiescence. Hence the detection of the white dwarf is more difficult. UZ Ser and SS Aur offer the possiblity of extending the range of systems for which the underlying white dwarf accreter has been analyzed with model atmospheres. We have applied the Massa-Fitzpatrick (2000) flux calibration correction to the archival IUE NEWSIPS SWP spectra of these two systems, obtained during dwarf nova quiescence. We have carried out high gravity model atmosphere using the codes TLUSTY195, SYNSPEC42, ROTIN and accretion disk synthetic spectra from the grid of Wade and Hubeny (1998). We have determined the physical properties of the white dwarf accreters, including temperature, gravity chemical abundances estimates, and the accretion rate during quiescence. We discuss our results in the context of the overall picture of accretion physics in dwarf novae and the effects of accretion on the white dwarf.
This research was supported in part by NSF grant AST 99-01955, NASA ADP grant NAG5-8388 and by summer research funding from the NASA- Delaware Space Grant Colleges Consortium.