The hot white dwarf HZ 43. II.
Abstract
The ultra soft X-ray spectra of the hot white dwarf HZ 43 in the range 40-200 A obtained recently by Bleeker et al. (1978) have been fitted by hydrogen-helium model atmospheres with various helium abundances and effective temperatures. It is shown that the soft X-ray spectrum is not consistent with these models. Satisfactory fits can be obtained with models which have an increasing helium abundance with depth in the atmosphere. For HZ 43 a pure hydrogen layer with a column mass of about 1 g/sq cm on top of a helium rich (helium abundance greater than or equal to 0.1 by number) atmosphere is consistent with the optical, ultraviolet, extreme ultraviolet and ultra soft X-ray data.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 1980
- Bibcode:
- 1980A&A....84..280H
- Keywords:
-
- Abundance;
- Helium;
- Stellar Atmospheres;
- White Dwarf Stars;
- X Ray Spectra;
- Atmospheric Models;
- Spectrum Analysis;
- Stellar Spectra;
- Astrophysics