Convective nonovershooting in stellar cores

Abstract

Mixing-length approximation appears to be consistent with the normal mode analysis of the transport of heat flux due to turbulent convection, in the stellar core as well as in the envelope of stars of a range of spectral types and luminosity classes that we have investigated. However, in spite of demonstrating the self-consistency of the mixing length approximation we do not see any justification for accepting any constant multiple of the mixing-length as a measure of the scale length for convective overshooting into the radiative zones. The convective velocity field in the interior of model of a star of ZAMS mass 10M_⊙ has been examined at three representative epochs during the main sequence phase, using the linear convective modes. The extent of overshooting is found to be less than O.1H_p in all the cases while the mixing-length within the convection zone is typically around 1/3H_p.