Detecting Convective Overshoot In Solar-Type Stars

Convective Envelopes in Solar - Type Stars :

The evolution of AGB stars with convective overshoot

The influence of extended convective mixing (overshoot) on asymptotic giant branch stellar evolution is investigated in detail. The extended mixing is treated timedependently, and the efficiency declines exponentially with the geometric distance from the convective boundary. It has been considered at all convective boundaries, including the He-flash convection zone in the intershell region whic...

Overshoot in Giant Stars

The concept of overshoot has already been considered for numerous cases in stellar evolution calculations. We explore the consequences of overshoot at the convection zone which forms during the He-flash (thermal pulse) in AGB stars. We find dramatic changes for the abundances within the intershell region as well as for the mechanism of the 3 dredge-up. That means that both the predicted evoluti...

Diffusive convective overshoot in core He - burning intermediate mass stars . I : the LMC metallicity

We present detailed evolutionary calculations focused on the evolution of intermediate mass stars with 3M ⊙ ≤ M ≤ 9M ⊙ of metallicity typical of the Large Magellanic Cloud (LMC), i.e. Z = 0.008. We compare carefully the models calculated by adopting a diffusive scheme for chemical mixing, in which nuclear burning and mixing are self-consistently coupled, while the eddy velocities beyond the for...

Asteroseismology of solar - type stars : signatures of convective and / or helium cores

Aims. Several frequency combinations are widely used in the analysis of stellar oscillations for comparisons between models and observations. In particular, the " small separations " can help constraining the stellar cores. We showed in a previous paper that they can change sign, in contradiction with the " asymptotic theory " , and that this behaviour could correspond to signatures of convecti...