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The Far-Ultraviolet Spectra of "Cool" PG1159 StarsWe present a comprehensive study of Far Ultraviolet Spectroscopic Explorer (FUSE) spectra (912-1190 A) of two members of the PG1159 spectral class, which consists of hydrogen-deficient (pre-) white dwarfs with effective temperatures in the range T(sub eff) = 75000-200000 K. As two representatives of the cooler objects, we have selected PG1707+427 (T(sub eff) = 85000 K) and PG1424+535 (T(sub eff) = 110000 K), complementing a previous study of the hotter prototype PG1159-035 (T(sub eff) = 140000 K). The helium-dominated atmospheres are strongly enriched in carbon and oxygen, therefore, their spectra are dominated by lines from C III-IV and O III-VI, many of which were never observed before in hot stars. In addition, lines of many other metals (N, F, Ne, Si, P, S, Ar, Fe) are detectable, demonstrating that observations in this spectral region are most rewarding when compared to the near-ultraviolet and optical wavelength bands. We perform abundance analyses of these species and derive upper limits for several undetected light and heavy metals including iron-group and trans-iron elements. The results are compared to predictions of stellar evolution models for neutron-capture nucleosynthesis and good agreement is found.
Document ID
20170004575
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Werner, K.
(Eberhard Karls Universitat Tuebingen Tuebingen, Germany)
Rauch, T.
(Eberhard Karls Universitat Tuebingen Tuebingen, Germany)
Kruk, J. W.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
May 15, 2017
Publication Date
October 15, 2015
Publication Information
Publication: Astronomy & Astrophysics
Publisher: EDP Sciences
Volume: 582
ISSN: 0004-6361
e-ISSN: 1432-0746
Subject Category
Astronomy
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN42416
Distribution Limits
Public
Copyright
Other

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