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Astron. Astrophys. 335, 1124-1129 (1998)

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New study of the quasi-molecular Lyman [FORMULA] satellites due to H-H and H-H+ collisions

N.F. Allard 1, 2, I. Drira 1, M. Gerbaldi 3, J. Kielkopf 4 and A. Spielfiedel 1

1 Observatoire de Paris-Meudon, Département Atomes et Molécules en Astrophysique, F-92195 Meudon Principal Cedex, France (drira@obspm.fr; annie.spielfiedel@obspm.fr)
2 CNRS Institut d'Astrophysique, 98 bis Boulevard Arago, F-75014 Paris, France (allard@iap.fr)
3 Institut d'Astrophysique, Université de Paris Sud XI, 98 bis Boulevard Arago, F-75014 Paris, France (gerbaldi@iap.fr)
4 Department of Physics, University of Louisville, Louisville, Ky 40292 USA (john@nimbus.physics.louisville.edu)

Received 8 January 1998 / Accepted 27 April 1998


We present new theoretical calculations of the total profile of the atomic hydrogen Lyman [FORMULA] spectral line perturbed by collisions with neutral hydrogen atoms and protons. The variation of the radiative dipole moment during the collision is taken into account. This leads to an increase in the amplitude of the main spectral line satellites and to a quantitative improvement of the synthetic spectra of [FORMULA] Bootis  stars compared to IUE observations.

Key words: atomic processes – line: profiles – stars: chemically peculiar – white dwarfs

Send offprint requests to: N. Allard

© European Southern Observatory (ESO) 1998

Online publication: June 26, 1998