Astron. Astrophys. 330, 782-790 (1998)

Satellites on the Lyman  line of atomic hydrogen
due to H-H⁺ collisions

N.F. Allard ^{1, 2}, J. Kielkopf ³ and N. Feautrier <sup>1

1</sup> Observatoire de Paris-Meudon, Département Atomes et Molécules en Astrophysique, F-92195 Meudon Principal Cedex, France
² CNRS Institut d'Astrophysique, 98 bis Boulevard Arago, F-75014 Paris, France
³ Department of Physics, University of Louisville, Louisville, Ky 40292 USA

Received 24 July 1997 / Accepted 12 September 1997

Abstract

We present new theoretical calculations of the total profile of the atomic hydrogen Lyman  spectral line perturbed by collisions with 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.

Key words: line: profiles stars: white dwarfs

Send offprint requests to: N. Allard

Contents

• 1. Introduction
• 2. Theory
  • 2.1. General expression for the spectrum
  • 2.2. Adiabatic representation
• 3. The correlation and spectral matrices
  • 3.1. Unperturbed spectrum and normalization
• 4. Uncorrelated perturbers approximation
  • 4.1. Adiabatic approximation at the one perturber level
• 5. Lyman in H-H⁺ collisions
  • 5.1. Transitions contributing to Lyman
  • 5.2. Diatomic potentials
  • 5.3. Dipole moments
• 6. Lyman  profile perturbed by protons
• 7. Collision induced absorption
• 8. Conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: January 16, 1998
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