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Paper: Stellar models with envelope overshoot
Volume: 13, The Formation and Evolution of Star Clusters
Page: 223
Authors: Alongi, M.; Bertelli, G.; Bressan, A.; Chiosi, C.
Abstract: We show that a certain amount of nonlocal overshoot at the base of the outer convective envelope of low mass stars while climbing along the RGB toward central helium ignition explains the shift of about 0.4 V mag required to bring the luminosity of the bump predicted in the theoretical RGB luminosity functions into agreement with the observational one. In addition to this, we find that an equal amount of overshoot from the convective envelope in intermediate mass stars greatly affects subsequent evolution in the H-R diagram, producing extended loops even for models computed with significant overshoot from the central convective core. These results cast light on the role played by core and envelope overshoot. The former provides the correct hydrogen and helium-burning lifetimes for intermediate mass stars, whereas the latter reproduces the observed morphology of young LMC clusters and the correct location of the bump in the RGB luminosity function of globular clusters.
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