Multi-wavelength spectrophotometry of EX Hydrae*
Universitäts-Sternwarte, Geismarlandstr. 11, 37083 Göttingen, Germany
Corresponding author: K. Beuermann, firstname.lastname@example.org
Accepted: 16 November 2001
We present phase-resolved infrared and optical spectrophotometry of the intermediate polar EX Hya supplemented by archival ultraviolet data. The spin-modulated emission from the accretion funnel and the emission from the accretion disk or ring contain substantial optically thin components. The white dwarf dominates the unmodulated flux in the ultraviolet and is identified by numerous absorption lines. Metal absorption in the accretion curtain may add to the observed spectral features. The secondary star is of spectral type M4 and is detected by its ellipsoidal modulation. We derive a distance of pc which makes EX Hydrae one of the closest cataclysmic variables with a known distance. The luminosity derived from the integrated overall spectral energy distribution is erg s-1. The accretion rate of g s-1 (for an 0.6 white dwarf) is in reasonable agreement with the rates expected from angular momentum loss by gravitational radiation and from the observed spin-up of the white dwarf.
Key words: stars: individual: EX Hydrae / cataclysmic variables / accretion
Based on observations made at the European Southern Observatory, Chile, with the ESO/MPI 2.2-m telescope in MPI time and at the Cerro Tololo Interamerican Observatory, Chile, under ESO programme ID 59.D-0724, and on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS .
© ESO, 2002