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Record 1 of 4256
The coolest DA white dwarfs detected at soft X-ray wavelengths
External Online Source: doi:10.1086/171581
Author and Affiliation:
Kidder, K. M.(NASA, Washington, DC, United States)
Holberg, J. B.(Arizona, University, Tucson, United States)
Barstow, M. A.(NASA, Washington, DC, United States)
Tweedy, R. W.(Leicester, University, United Kingdom)
Wesemael, F.(Montreal, Universite, Montreal, Canada)
Abstract: New soft X-ray/EUV photometric observations of the DA white dwarfs KPD 0631 + 1043 = WD 0631 + 107 and PG 1113 + 413 = WD 1113 + 413 are analyzed. Previously reported soft X-ray detections of three other DAs and the failure to detect a fourth DA in deep Exosat observations are investigated. New ground-based spectra are presented for all of the objects, with IUE Ly-alpha spectra for some. These data are used to constrain the effective temperatures and surface gravities. The improved estimates of these parameters are employed to refer a photospheric He abundance for the hotter objects and to elucidate an effective observational low-temperature threshold for the detection of pure hydrogen DA white dwarfs at soft X-ray wavelengths.
Publication Date: Jul 20, 1992
Document ID:
19920065506
(Acquired Nov 22, 1995)
Accession Number: 92A48130
Subject Category: ASTROPHYSICS
Document Type: Journal Article
Publication Information: Astrophysical Journal, Part 1 (ISSN 0004-637X); 394; 1, Ju; 288-297
Publisher Information: United States
Contract/Grant/Task Num: NAG5-434
Organization Source: NASA; Washington, DC, United States
NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 10p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: STELLAR SPECTROPHOTOMETRY; WHITE DWARF STARS; X RAY ASTRONOMY; ABUNDANCE; HELIUM; IUE; LYMAN ALPHA RADIATION; STELLAR ATMOSPHERES; STELLAR TEMPERATURE
Imprint And Other Notes: Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 394, no. 1, July 20, 1992, p. 288-297. Research supported by NASA, SERC, NSERC, and FCAR.
Miscellaneous Notes: Research supported by NASA, SERC, NSERC, and FC
Availability Source: Other Sources
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