ar X iv : a st ro - p h / 05 09 46 4 v 1 1 5 Se p 20 05 1 3 D SIMULATION OF CONVECTION AND SPECTRAL LINE FORMATION IN A - TYPE STARS
نویسندگان
چکیده
We present first realistic numerical simulations of 3D radiative convection in the surface layers of main sequence A-type stars with T eff = 8000 K and 8500 K, log g = 4.4 and 4.0, recently performed with the CO 5 BOLD radiation hydrodynamics code. The resulting models are used to investigate the structure of the H+He I and the He II convection zones in comparison with the predictions of local and non-local convection theories, and to determine the amount of 'overshoot' into the stable layers below the He II convection zone. The simulations also predict how the topology of the photospheric granulation pattern changes from solar to A-type star convection. The influence of the photospheric temperature fluctuations and velocity fields on the shape of spectral lines is demonstrated by computing synthetic line profiles and line bisectors for some representative examples, allowing us to confront the 3D model results with observations.
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