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ROSAT EUV and soft X-ray studies of atmospheric composition and structure in G191-B2BPrevious studies of the hot DA white dwarf GI91-B2B have been unable to determine whether the observed soft X-ray and EUV opacity arises from a stratified hydrogen and helium atmosphere or from the presence of trace metals in the photosphere. New EUV and soft X-ray photometry of this star, made with the ROSAT observatory, when analyzed in conjunction with the earlier data, shows that the stratified models cannot account for the observed fluxes. Consequently, we conclude that trace metals must be a substantial source of opacity in the photosphere of G191-B2B.
Document ID
Document Type
Reprint (Version printed in journal)
Barstow, M. A. (Leicester Univ. United Kingdom)
Fleming, T. A. (Max-Planck-Inst. fuer Extraterrestrische Physik Garching, Germany)
Finley, D. S. (California Univ. Berkeley, United States)
Koester, D. (Louisiana State Univ. Baton Rouge, United States)
Diamond, C. J. (Birmingham Univ. United Kingdom)
Date Acquired
August 16, 2013
Publication Date
February 1, 1993
Publication Information
Publication: Royal Astronomical Society, Monthly Notices
Volume: 260
Issue: 3
ISSN: 0035-8711
Subject Category
Distribution Limits