EX-111 thermal emission from hot white dwarfs: the suggested He abundance-temperature correlation. EX-112: the unique emission line white dwarf star GD 356. Semiannnual status report, 1 December 1985-1 June 1986
Progress in the EXOSAT data analysis program is reported. EXOSAT observations for four white dwarfs (WD1031-115, WD0004+330, WD1615-154, and WD0109-264) were obtained. Counting rates were unexpectedly low, indicating that these objects have a substantial amount of x-ray absorbing matter in their photosheres. In addition, soft x-ray pulsations characterized by a 9.25 minute cycle were discovered in the DA white dwarf V471 Tauri. A residual x-ray flux from the K dwarf companion can be seen during the white dwarf eclipse at orbital phase 0.0. Pronounced dips in the soft x-ray light curve occur at orbital phases 0.15, 0.18, and 0.85. The dips may be correlated with the triangular Lagrangian points of the binary orbit. Smaller dips at phases near the eclipse may be associated with cool loops in the K star corona. Data for the white dwarf H1504+65 was also analyzed. This object is particularly unusual in that its photoshere is devoid of hydrogen and helium. Finally, existing data on the white dwarf Sirius B were analyzed to see what constraints from other data can be placed on the properties of this star. Interrelationships between radius, rotational velocity, and effective temperature were derived.
- Research Organization:
- Delaware Univ., Newark (USA)
- OSTI ID:
- 7169102
- Report Number(s):
- N-86-31470; NASA-CR-176866; NAS-1.26:176866
- Country of Publication:
- United States
- Language:
- English
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Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BINARY STARS
DATA
DWARF STARS
EMISSION SPECTRA
EXPERIMENTAL DATA
INFORMATION
NUMERICAL DATA
PHOTOSPHERE
SOLAR ATMOSPHERE
SPECTRA
STARS
STELLAR ATMOSPHERES
WHITE DWARF STARS
X-RAY SPECTRA