ORFEUS Observations of AM Herculis
JOHN C. RAYMOND, Christopher W. Mauche, Stuart Bowyer, Mark Hurwitz · The Astrophysical Journal · 1995
The ORFEUS telescope has observed AM Her in its high optical state at high spectral resolution in the 912-1176 Å band. Spectra at two phases show O VI emission lines with a broad and narrow component structure similar to that of the optical emission lines. We find that the O VI lines are optically thick, and that the densities in the broad- and narrow-component regions differ by a factor of 100. The most puzzling aspect of the observations is the continuum, which is softer than expected, but does not show definite Lyman absorption lines. We discuss the implications for the "soft X-ray excess" of AM Her stars.