A Role for Superadiabatic Convection in Low Mass Structures?

We compute the structure of stars of mass M 0:5M starting from the pre{main sequence and employing diierent assumptions on the convection model, in particular dropping the Mixing Length Theory (MLT) and adopting a Full Spectrum of Turbulence (FST) mod-elization (Canuto and Mazzitelli 1991, Canuto, Goldman and Mazzitelli 1996). In the FST framework, convection in the upper stellar envelope can be so ineecient that there is a thin superadiabatic layer. The resulting T ee may diier up to 200K, according to the detailed treatment of the convection model, a result which can not be found by changing the l=H P value in the MLT models within acceptable values. It results important to introduce the FST treatment of convection also in the model atmospheres, which are necessary to full understanding of the observational characteristics of low mass stars.