Lithium depletion in late-type dwarfs

Using a self-consistent dynamic theory of non-local convection, the atmospheric lithiumabundance depletion values of a series of stellar evolutionary models withM = 0.725–1.5 M are calculated, and the results show that the general observed properties of lithium abundance in lower-main-sequence stars can be reproduced by overshooting mixing and gravitational settling. After a careful study of the mechanisms of lithium depletion in stars, it is concluded that overshooting mixing and microdiffusion induced by gravitational settling and radiative acceleration are the two primary depletion mechanisms: for warm stars with M ≥ 1.1 M (or Te ≥ 6100 K) microdiffusion dominates, while it is the other way round for cooler objects with M ≤ 1 M (or Te ≤ 5800 K).