Astron. Astrophys. 327, 1107-1113 (1997)

A spectroscopic study
of the long-period dwarf nova DX Andromedae

Albert Bruch ^{* 1}, Sonja Vrielmann ^{1, 2, 3}, Frederic V. Hessman ², Alexander Kochsiek ¹ and Thomas Schimpke <sup>1

1</sup> Astronomisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, D-48149 Münster, Germany
² Universitäts-Sternwarte Göttingen, Geismarlandstraße 11, D-37083 Göttingen, Germany
³ School of Physics & Astronomy, North Haugh, St. Andrews, KY16 9SS, UK

Received 24 April 1996 / Accepted 12 November 1996

Abstract

We present time-resolved spectra of the double-lined dwarf nova DX And in quiescence from two campaigns in 1989 and 1993. Using an unusual method, we have reconstructed the radial velocity amplitudes and phases of the absorption and emission line components from data suffering from serious wavelength calibration problems by measuring the relative motions of as well as the phase shift between the two line systems. We are thus able to refine the orbital period and to determine a long-term ephemeris. The relative contribution of the primary to the total light was measured as a function of wavelength, permitting to correct the absorption line spectrum for the veiling effect. The secondary star exhibits several spectral peculiarities: in addition to the enhanced Ca I absorption lines reported previously, we find several Cr I lines to be significantly stronger than in a comparison star of similar spectral type.

Key words: stars: binaries: close stars: novae, cataclysmic variables stars: individual: DX And

* Visiting Astronomer, German-Spanish Astronomical Centre, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy

Send offprint requests to: Albert Bruch

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Contents

• 1. Introduction
• 2. Observations and reductions
• 3. Radial velocity measurements
  • 3.1. The relative radial velocities
  • 3.2. The absolute radial velocities
  • 3.3. The reconstructed radial velocity amplitudes and phases
• 4. The orbital period
• 5. The secondary spectrum of DX And
  • 5.1. Determination of the veiling
  • 5.2. The absorption line spectrum
• 6. Summary
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: April 6, 1998
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