Nonlinear Pulsations of Convective Stellar Models

Nonlinear Pulsations of Convective Stellar Models

We review the numerical modelling of the nonlinear pulsations of classical variable stars with hydrocodes that include the effects of turbulent convection. Despite their simplicity these turbulent convective recipes appear to remove many of the difficulties that radiative codes faced. In particular, the numerical modelling of double mode pulsations has become possible.

A simple convection model for selfgravitating fluid dynamics Time-dependent convective energy transfer in protostars and nonlinear stellar pulsations

We describe a relatively simple time-dependent convection model that can be coupled to the equations of radiation hydrodynamics. We show that it behaves in a physically plausible way in protostellar collapse flows and is quantitatively correct for nonlinear RR-Lyrae pulsations and the Sun. Together with the equations of radiation hydrodynamics the model closely approximates the classical stella...

RADIATIVE OPACITIES AND STEllAR PULSATIONS

Stellar pulsations excited by a scattered mass

We compute the energy spectra of the gravitational signals emitted when a mass m0 is scattered by the gravitational field of a star of mass M >> m0. We show that, unlike black holes in similar processes, the quasi-normal modes of the star are excited, and that the amount of energy emitted in these modes depends on how close the exciting mass can get to the star. PACS numbers: 04.30.-w, 04.40.Dg...

The role of negative buoyancy in convective Cepheid models. Double-mode pulsations revisited

The longstanding problem of modeling double-mode behaviour of classical pulsators was solved with the incorporation of turbulent convection into pulsation hydrocodes. However, the reasons for the computed double-mode behaviour were never clearly identified. In our recent papers (Smolec & Moskalik 2008a,b) we showed that the double-mode behaviour results from the neglect of negative buoyancy eff...