We perform two-dimensional (2D) numerical simulations of core convection for zero-age main-sequence stars covering a mass
range from 3 to 20 M. The simulations are performed with the fully compressible time-implicit code MUSIC. We study the
efficiency of overshooting, which describes the ballistic process of convective flows crossing ...
We perform two-dimensional (2D) numerical simulations of core convection for zero-age main-sequence stars covering a mass
range from 3 to 20 M. The simulations are performed with the fully compressible time-implicit code MUSIC. We study the
efficiency of overshooting, which describes the ballistic process of convective flows crossing a convective boundary, as a function
of stellar mass and luminosity. We also study the impact of artificially increasing the stellar luminosity for 3 M models. The
simulations cover hundreds to thousands of convective turnover time-scales. Applying the framework of extreme plume events
previously developed for convective envelopes, we derive overshooting lengths as a function of stellar masses. We find that the
overshooting distance (dov) scales with the stellar luminosity (L) and the convective core radius (rconv). We derive a scaling law
dov ∝ L1/3r1/2 conv, which isimplemented in a one-dimensionalstellar evolution code and the resulting stellar models are compared to
observations. The scaling predicts values for the overshooting distance that significantly increase with stellar mass, in qualitative
agreement with observations. Quantitatively, however, the predicted values are underestimated for masses 10 M. Our 2D
simulations show the formation of a nearly adiabatic layer just above the Schwarzschild boundary of the convective core, as
exhibited in recent three-dimensionalsimulations of convection. The most luminous modelsshow a growth in size with time of the
nearly adiabatic layer. This growth seemsto slow down asthe upper edge of the nearly adiabatic layer gets closer to the maximum
overshooting length and as the simulation time exceeds the typical thermal diffusive time-scale in the overshooting layer.