Astron. Astrophys. 326, 203-210 (1997)

Non-linear models for the pulsating post-AGB star SAO 96709: metallic lines

L. Jeannin ¹, A.B. Fokin ^{1, 2}, D. Gillet ³ and I. Baraffe <sup>1

1</sup> Centre de Recherche Astronomique de Lyon (UMR 5574, CNRS), Ecole Normale Supérieure de Lyon, 46 allée d'Italie,
F-69364 Lyon Cedex 07, France
² Institute of Astronomy of the Russian Academy of Sciences, 48 Pjatnitskaya Str., Moscow 109017 Russia
³ Observatoire de Haute-Provence, CNRS, F-04870 Saint Michel l'Observatoire, France

Received 27 February 1997 / Accepted 21 April 1997

Abstract

We have performed a set of nonlinear pulsating models for post-AGB stars and have reconstructed the spectral lines for two chemical elements (Ba II, C I). The present analysis is devoted to the interpretation of recent spectroscopic observations of the pulsating post-AGB star SAO 96709. We confirm our earlier result (Jeannin et al. 1996) that the dominant pulsation mode is the first overtone and find an increase of the second overtone in the Fourier spectrum with decreasing mass and metallicity Z. The Doppler velocities deduced from the theoretical line profiles vary from 10 to 15 km.s^-1 and are in a good agreement with observations. In order to reproduce the observed line broadening, a very large microturbulent velocity has to be introduced, probably with some variations during the pulsational cycle.

Key words: stars: oscillations stars: post-AGB shock waves turbulence stars: SAO 96709

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations: present status
• 3. Nonlinear models
• 4. Atmospheric structure
• 5. Metallic lines
  • 5.1. Line profile modelling
  • 5.2. Doppler shifts and line widths
  • 5.3. Sources of broadening
  • 5.4. Discussion
• 6. Conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: April 20, 1998
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