New study of the quasi-molecular Lyman-γ satellites due to H-H+ collisions
Abstract
Context: Quasi-molecular line satellites in the red wings of Lyman series of atomic hydrogen have been identified in the spectra of hydrogen-rich white dwarfs. These features are produced by radiative collisions.
Aims: Structures observed about 995 Åin the Lyman-γ wing of hot white dwarfs have been shown to be caused by quasi-molecular absorption of H2+ molecules.
Methods: Improvements to previous theoretical calculations of the Lyman-γ line profiles can be achieved by using a unified theory that takes into account the dependence of the dipole moments on internuclear distance during the collision.
Results: For the first time, we have computed the transition dipole moments. We measure a significant increase in the region of the formation of the satellites, which alters the general shape of the profile.
Conclusions: A large increase in the strength of the two main satellites at 992 and 996 Å leads to a deeper broad absorption in the synthetic spectra, which should improve the comparison with observation as previous predicted Lyman-γ satellites were too weak.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- November 2009
- DOI:
- 10.1051/0004-6361/200912511
- Bibcode:
- 2009A&A...506..993A
- Keywords:
-
- line: profiles;
- stars: white dwarfs