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 .