We study lithium depletion in low-mass and solar-like stars as a function of time , using a new diffusion coefficient describing extra-mixing taking place at the bottom of a convective envelope .
This new form is motivated by multi-dimensional fully compressible , time implicit hydrodynamic simulations performed with the MUSIC code .
Intermittent convective mixing at the convective boundary in a star can be modeled using extreme value theory , a statistical analysis frequently used for finance , meteorology , and environmental science .
In this letter , we implement this statistical diffusion coefficient in a one-dimensional stellar evolution code , using parameters calibrated from multi-dimensional hydrodynamic simulations of a young low-mass star .
We propose a new scenario that can explain observations of the surface abundance of lithium in the Sun and in clusters covering a wide range of ages , from \sim 50 Myr to \sim 4 Gyr .
Because it relies on our physical model of convective penetration , this scenario has a limited number of assumptions .
It can explain the observed trend between rotation and depletion , based on a single additional assumption , namely that rotation affects the mixing efficiency at the convective boundary .
We suggest the existence of a threshold in stellar rotation rate above which rotation strongly prevents the vertical penetration of plumes and below which rotation has small effects .
In addition to providing a possible explanation for the long standing problem of lithium depletion in pre-main sequence and main sequence stars , the strength of our scenario is that its basic assumptions can be tested by future hydrodynamic simulations .