Quasi-molecular lines in Lyman wings of cool DA white dwarfs. Application to FUSE observations of G 231-40
Abstract
We present new theoretical calculations of the total line profiles of Lyman alpha and Lyman beta which include perturbations by both neutral hydrogen and protons and all possible quasi-molecular states of H2 and H2+. They are used to improve theoretical modeling of synthetic spectra for cool DA white dwarfs. We compare them with FUSE observation of G 231-40. The appearance of the line wings between Lyman alpha and Lyman beta 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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2002
- DOI:
- 10.1051/0004-6361:20021141
- arXiv:
- arXiv:astro-ph/0208372
- Bibcode:
- 2002A&A...394..647H
- Keywords:
-
- line: profiles;
- radiation mechanisms: general;
- stars: atmospheres;
- stars: individual: G231-40;
- white dwarfs;
- ultraviolet: stars;
- Astrophysics
- E-Print:
- 6 pages, 4 figures, accepted for publication in Astronomy and Astrophysics