Time‐Dependent Turbulent Convection in 1D Radiation Hydrodynamics of Pulsating Stars

Abstract

Abstract: Due to the lack of a self‐consistent convection theory, each model of turbulent convection has to pass through several tests based on detailed comparisons with observations of real astrophysical objects. In this context nonlinear investigations of radially pulsating stars play an important role. They provide a unique opportunity to confront results of model calculations with a huge, detailed and accurate material of observational data.Using a state‐of‐the‐art numerical technique we investigate the nonlinear behavior of radially pulsating stars by solving the full time‐dependent system of radiation hydrodynamics including a time‐dependent turbulent convection model.As a first example we discuss nonlinear models of RR Lyrae stars. We present fundamental as well as first overtone lightcurves for two sets of stellar parameters. A standard Fourier decomposition is used to confront the resulting light and radial velocity variations with recent observations and we show that well‐known problems like the phase discrepancy problem or the problem of stable nonlinear double mode models can be treated.