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Record Details

Record 20 of 10607
The constitution of the atmospheric layers and the extreme ultraviolet spectrum of hot hydrogen-rich white dwarfs
Author and Affiliation:
Vennes, Stephane(Delaware, University, Newark)
Abstract: An analysis is presented of the atmospheric properties of hot, H-rich, DA white dwarfs that is based on optical, UV, and X-ray observations aimed at predicting detailed spectral properties of these stars in the range 80-800 A. The divergences between observations from a sample of 15 hot DA white dwarfs emitting in the EUV/soft X-ray range and pure H synthetic spectra calculated from a grid of model atmospheres characterized by Teff and g are examined. Seven out of 15 DA stars are found to consistently exhibit pure hydrogen atmospheres, the remaining seven stars showing inconsistency between FUV and EUV/soft X-ray data that can be explained by the presence of trace EUV/soft X-ray absorbers. Synthetic data are computed assuming two other possible chemical structures: photospheric traces of radiatively levitated heavy elements and a stratified hydrogen/helium distribution. Predictions about forthcoming medium-resolution observations of the EUV spectrum of selected hot H-rich white dwarfs are made.
Publication Date: May 10, 1992
Document ID:
19920054155
(Acquired Nov 22, 1995)
Accession Number: 92A36779
Subject Category: ASTROPHYSICS
Document Type: Journal Article
Publication Information: Astrophysical Journal, Part 1 (ISSN 0004-637X); 390; 2, Ma
Publisher Information: United States
Contract/Grant/Task Num: NSF AST-87-20530; NAS5-30180; NAG5-972
Financial Sponsor: NASA; United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 12p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: EXTREME ULTRAVIOLET RADIATION; HOT STARS; STELLAR ATMOSPHERES; STELLAR SPECTRA; WHITE DWARF STARS; X RAY STARS; ATMOSPHERIC STRATIFICATION; ULTRAVIOLET ASTRONOMY; ULTRAVIOLET SPECTRA; X RAY ASTRONOMY; X RAY SPECTRA
Imprint And Other Notes: Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 390, no. 2, May 10, 1992, p. 590-601.
Availability Source: Other Sources
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