New evidence on the nature of the soft X-ray source in AM Herculis from HEAO 1.
Abstract
Results are reported for scanning observations of AM Herculis from HEAO 1 during the period September 22-October 12, 1977. The soft X-ray light curve constructed from the observations shows considerable scatter in intensity, together with clear evidence for a residual flux during X-ray minimum. At X-ray maximum the flux in the energy range 0.15-0.5 keV is typically 8 x 10 to the -10th power erg/sq cm per sec. The spectrum of AM Her is characterized by a sharp turnover at 0.2 keV and is well described by a blackbody model with absorption. There is no appreciable change in the spectrum with binary phase. The present observations, when combined with theoretical models, imply that the soft X-rays are produced by the heated surface of the degenerate dwarf component, and that the surface has a temperature of approximately 400,000 K and a luminosity about 30 times that observed at optical or hard X-ray wavelengths. AM Her is predicted to be a spectacular UV source, with an intrinsic UV luminosity comparable to that in soft X-rays.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1978
- DOI:
- 10.1086/182821
- Bibcode:
- 1978ApJ...226L..17T
- Keywords:
-
- Astronomical Spectroscopy;
- Binary Stars;
- Ultraviolet Astronomy;
- X Ray Stars;
- Black Body Radiation;
- Heao 1;
- Light Curve;
- Luminous Intensity;
- White Dwarf Stars;
- Astrophysics;
- AM Herculis:Soft X Rays;
- Spectra:X-Ray Binaries