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Record Details

Record 50 of 1326
Photospheric soft X-ray emission from hot DA white dwarfs
External Online Source: doi:10.1086/161789
Author and Affiliation:
Wesemael, F.(Montreal, Universite)
Raymond, J. C.(Sao Paulo, Universidade, Sao Paulo, Brazil)
Kahn, S. M.(Montreal Univ. Quebec, Canada)
Liebert, J.(Montreal Univ. Quebec, Canada)
Steiner, J. E.(Montreal Univ. Quebec, Canada)
Shipman, H. L.(Montreal Univ. Quebec, Canada)
Abstract: The Einstein Observatory's imaging proportional counter has detected 150-eV soft X-ray radiation from the four hot DA white dwarfs EG 187, Gr 288 and 289, and LB 1663. The observed pulse height spectra suggest that the emission is generated by hot photospheres whose T(eff) lie in the 30,000-60,000 K range. The IUE spacecraft UV spectra and H-beta line profiles for the four stars have been fitted, along with the X-ray fluxes, with a grid of hot, high gravity, homogeneous model atmospheres of mixed H-He composition. In all cases, the data require the presence of some X-ray opacity in the photosphere. Attention is given to the implications of this result in the context of white dwarf surface layer diffusion theories. Also noted are the limits imposed on the hot white dwarf population by the Einstein Medium Sensitivity Survey.
Publication Date: Mar 01, 1984
Document ID:
19840044890
(Acquired Nov 28, 1995)
Accession Number: 84A27677
Subject Category: ASTROPHYSICS
Document Type: Journal Article
Publication Information: Astrophysical Journal, Part 1 (ISSN 0004-637X); 278; 255-265
Publisher Information: United States
Contract/Grant/Task Num: NAS8-30753; NSF AST-81-15095; NAG5-87; NAG8-370; NAG5-38
Financial Sponsor: NASA; United States
Organization Source: Montreal Univ. Quebec; Cambridge, MA, United States
Harvard-Smithsonian Center for Astrophysics; Cambridge, MA, Brazil
Sao Paulo Univ.; Montreal Quebec, Canada
Observatoire du Mont Megantic
Description: 11p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: EMISSION SPECTRA; PHOTOSPHERE; STELLAR SPECTROPHOTOMETRY; WHITE DWARF STARS; X RAY SPECTRA; ABUNDANCE; H BETA LINE; IUE; PROPORTIONAL COUNTERS; STELLAR EVOLUTION; STELLAR TEMPERATURE; ULTRAVIOLET SPECTRA
Imprint And Other Notes: Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 278, March 1, 1984, p. 255-265. Research supported by the Natural Sciences and Engineering Research Council of Canada and John Simon Guggenheim Memorial Foundation.
Miscellaneous Notes: Research supported by the Natural Sciences and Engineering Research Council of Canada and John Simon Guggenheim Memorial Foundation
Availability Source: Other Sources
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