X-ray emission from vibrating white dwarfs.
Abstract
It had been proposed previously that regularly pulsating X-ray sources (Cen X-3 and Her X-1) may be the result of vibrating white dwarfs sending shock waves into their atmospheres. We investigate the hydrodynamics and X-ray production of such objects. The relevant parameters are discussed, and detailed numerical calculations are carried out for a series of cases. The results depend very strongly on whether the parameter values are physically realizable or not. The photospheric radiation flux cools hot atmospheric material by Compton recoil. For physically reasonable amplitudes of oscillation a mismatch between the stellar oscillation and the acoustic response of the atmosphere makes energy coupling to the atmosphere very inefficient. These two effects lead to multi-keV X-ray powers many orders of magnitude too low to explain the observations, in disagreement with earlier work.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1974
- DOI:
- 10.1086/153178
- Bibcode:
- 1974ApJ...193..429K
- Keywords:
-
- Pulsed Radiation;
- Radiant Cooling;
- Stellar Atmospheres;
- Thermal Radiation;
- White Dwarf Stars;
- X Ray Sources;
- Astronomical Models;
- Atmospheric Temperature;
- Compton Effect;
- Hydrodynamics;
- Photosphere;
- Radiant Flux Density;
- Shock Waves;
- Astrophysics