Time-resolved spectroscopy and photometry of the dwarf nova FS Aurigae in quiescence*
Department of Astronomy and Mechanics, Udmurtia State University, Universitetskaia, 1, Izhevsk 426034, Russia
Corresponding author: email@example.com
Accepted: 16 November 2001
We present results of non-simultaneous time-resolved photometric and spectroscopic observations of the little-studied dwarf nova FS Aur in quiescence. The spectrum of FS Aur shows strong and broad emission lines of hydrogen and He I, and of weaker He II and C III/N III blend, similar to other quiescent dwarf novae. All emission lines are single-peaked, however their form varies with orbital phase. Absorption lines from a late-type secondary are not detected. From the radial velocity measurements of the hydrogen lines Hβ and Hγ we determined a most probable orbital period . This period agrees well with the 00595 ± 00001 estimate by Thorstensen et al. (1996). On the other hand, the period of photometric modulations is longer than the spectroscopic period and can be estimated as 3 hours. Longer time coverage during a single night is needed to resolve this problem. Using the semi-amplitude of the radial velocities, obtained from measurements of hydrogen and helium lines, and some empirical and theoretical relations we limited the basic parameters of the system: a mass ratio , a primary mass , a secondary mass , and an inclination angle . Doppler tomography has shown at least two bright regions in the accretion disk of FS Aur. The first, brighter spot is located at phase about 0.6. The second spot is located opposite the first one and occupies an extensive area at phases about .
Key words: accretion, accretion disks / stars: binaries: spectroscopic / stars: cataclysmic variables / stars: individual: FS Aur
© ESO, 2002