Three-dimensional radiative hydrodynamical simulations of sun-like stars

P. Demarque1,L.H. Li1,F.J. Robinson1, S. Sofia1, & D.B. Guenther2
1 Department of Astronomy, Yale University, New Haven, CT 06520-8101, USA
1 Department of Astronomy & Physics, Saint Mary's University, Halifax, NS B3H 3C3, Canada

 

Based on our success in simulating the outer layers of the sun (Robinson et al. 2002), we have extended our analysis to earlier and later stages of solar evolution. Of the many quantities that can be accurately computed in the 3D simulations, we present the turbulent velocities and the superadiabatic gradient for the zero-age main sequence, main sequence turn-off, sub-giant and giant models. Each simulation includes the most complete physics to date, i.e. physically realistic radiative-hydrodynamics, realistic opacities and equation of state, including full treatment of the ionization of H and He. In a recent publication, Li et al. (2002) have shown how to incorporate turbulence into 1D stellar models. By applying this method to the subgiant model, we construct a new equilibrium model of the star. Then using Guenther's (1994) pulsation code, the adiabatic frequencies of non-radial oscillations of this stellar model are calculated. By incorporating the convective velocities from the corresponding 3D simulations into the pulsation code, it is possible to test which p-modes are excited in the subgiant model. Using the above approach, which has proven successful in predicting the excitation of both radial and non-radial modes in the sun, we intend to predict the frequencies and excitation of observable p-modes in other sun-like stars. The opportunity to test our modeling by observation will soon be provided by several dedicated asteroseismology space missions (MOST, to be launched in 2002; then COROT, MONS and EDDINGTON). This research was supported in part by NASA grant NAG5-8406.

 
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