FM17p.32 — 2D and 3D Models of Convective Turbulence and Oscillations in Intermediate-Mass Main-Sequence Stars

Date & Time

Aug 10th at 6:00 PM until 6:00 PM




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Author(s): Joyce Ann Guzik3, Taylor H. Morgan2, Nicholas J. Nelson3, Catherine Lovekin4, Irina N. Kitiashvili5, Nagi N. Mansour5, Alexander Kosovichev1

Institution(s): 1. Big Bear Solar Observatory, 2. Brigham Young University, 3. Los Alamos National Laboratory, 4. Mount Allison University, 5. NASA Ames Research Center

We present multidimensional modeling of convection and oscillations in main-sequence stars somewhat more massive than the sun, using three separate approaches: 1) Applying the spherical 3D MHD ASH (Anelastic Spherical Harmonics) code to simulate the core convection and radiative zone. Our goal is to determine whether core convection can excite low-frequency gravity modes, and thereby explain the presence of low frequencies for some hybrid gamma Dor/delta Sct variables for which the envelope convection zone is too shallow for the convective blocking mechanism to drive g modes; 2) Using the 3D planar ‘StellarBox’ radiation hydrodynamics code to model the envelope convection zone and part of the radiative zone. Our goals are to examine the interaction of stellar pulsations with turbulent convection in the envelope, excitation of acoustic modes, and the role of convective overshooting; 3) Applying the ROTORC 2D stellar evolution and dynamics code to calculate evolution with a variety of initial rotation rates and extents of core convective overshooting. The nonradial adiabatic pulsation frequencies of these nonspherical models will be calculated using the 2D pulsation code NRO of Clement. We will present new insights into gamma Dor and delta Sct pulsations gained by multidimensional modeling compared to 1D model expectations.