Empirical constraints on convective core overshoot

In stellar evolution calculations, the local pressure scale height is often used to empirically constrain the amount of convective core overshoot. How ever, this method brings unsatisfactory results for low-mass stars (less th an or equal to1.1-1.2 M-circle dot for Z=Z(circle dot)) for which have very small cores or no convective core at all. Following Roxburgh's integral co nstraint, we implemented an upper limit of overshoot within the conventiona l method of alpha parameterization to remove an overly large overshoot effe ct on low-mass stars. The erroneously large effect of core overshoot due to the failure of alpha parameterization can be effectively corrected by limi ting the amount of overshoot to less than or equal to 15% of the core radiu s; 15% of the core radius would be a proper limit of overshoot, which can b e implemented in a stellar evolution code for intermediate- to low-mass sta rs. The temperature structure of the overshoot region does not play a cruci al role in stellar evolution since this transition region is very thin.