Issue |
A&A
Volume 394, Number 2, November I 2002
|
|
---|---|---|
Page(s) | 647 - 651 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20021141 | |
Published online | 15 October 2002 |
Quasi-molecular lines in Lyman wings of cool DA white dwarfs
Application to
observations of G 231–40
1
Institut d'Astrophysique de Paris, CNRS, 98 boulevard Arago, 75014 Paris, France
2
Observatoire de Paris-Meudon, LERMA, 92195 Meudon Principal Cedex, France
3
NOAO, 950 North Cherry Avenue, Tucson, AZ 85726, USA
4
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
Corresponding author: G. Hébrard, hebrard@iap.fr
Received:
3
April
2002
Accepted:
5
August
2002
We present new theoretical calculations of the total line
profiles of Lyman α and Lyman β which include
perturbations by both neutral hydrogen and protons and all possible
quasi-molecular states of H2 and H. They are used to improve
theoretical modeling of synthetic spectra for cool DA white dwarfs.
We compare them with FUSEobservation of G 231–40.
The appearance of the
line wings between Lyman α and Lyman β is shown to be
sensitive to the relative abundance of hydrogen ions and neutral atoms,
and thereby to provide a temperature diagnostic for
stellar atmospheres and laboratory plasmas.
Key words: line: profiles / radiation mechanisms: general / stars: atmospheres / stars: individual: G231-40 / white dwarfs / ultraviolet: stars
© ESO, 2002
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