Multi-wavelength spectrophotometry of EX Hydrae*
Universitäts-Sternwarte, Geismarlandstr. 11, 37083 Göttingen, Germany
Corresponding author: K. Beuermann, beuermann@uni-sw.gwdg.de
Received:
1
October
2001
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