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PhD Thesis

Title: Study of the convection-pulsations coupling and application to Cepheid stars
Defense: 18th November 2009
Supervisor: Boris Dintrans
Abstract:
Cepheid variables are pulsating stars that oscillate on radial acoustic modes. Their oscillations are sustained by a mechanism linked with opacity in ionisation regions, the κ-mechanism, where κ denotes the opacity. For now, the influence of the convective motions on this instability is not well known theoretically. The purpose of this thesis is to study this convection-pulsation coupling that occurs in cold Cepheids.

We have performed a linear stability analysis to get the most unstable models excited by the κ-mechanism. By starting from these favourable setups, we have computed direct numerical simulations. The nonlinear saturation was then addressed in presence of a convective zone.
Keywords: Hydrodynamics - Instabilities - Stars: oscillations - Convection - Methods: numerical

You can download the manuscript (in French).