The Treatment of Overshooting in Stellar Modelling: Instantaneous and Diffusive Approach

Convective overshoot is a physical mechanism for which no recipe based on first principles is available; hence the necessity of assuming some parametrisations, which undermine the predictive power of the current generation of stellar models. We evidentiate the non local aspects of the convective phenomenon particularly in the proximities of the convective borders, and identify some cases when the use of a diffusive rather than the classic instantaneous approach to describe overshooting is highly recommended