Related papers: The diffusive overshooting approach on Li abundanc…
Helioseismic investigation has suggested to apply the turbulent convection models (TCMs) to the convective overshooting. Using the turbulent velocity in the overshooting region determined by the TCM, one can deal with the overshooting…
Based on radiation hydrodynamics modeling of stellar convection zones, a diffusion scheme has been devised describing the downward penetration of convective motions beyond the Schwarzschild boundary (overshoot) into the radiative interior.…
The classical 'ballistic' overshoot models show some contradictions and are not consistence with numerical simulations and asteroseismic studies. Asteroseismic studies imply that overshoot is a weak mixing process. Diffusion model is…
Evolution of the 7Li abundance in the convection zone of the Sun during different stages of its life time is considered to explain its low photospheric value in comparison with that of the solar system meteorites. Lithium is intensively and…
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…
Turbulent convection models are thought to be good tools to deal with the convective overshooting in the stellar interior. However, they are too complex to be applied in calculations of stellar structure and evolution. In order to…
Overshooting and semiconvection are among the most uncertainties in the evolution of massive stars. Complete mixing over a certain distance beyond the convective boundary (Stothers \& Chin 1985) and an exponentially decaying diffusion…
Stellar models with masses ranging from 0.5 to $1.3~M_\odot$ were constructed in order to compare to young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of…
Mixing mechanisms bring the Li from the base of the convective zone to deeper and warmer layers where it is destroyed. These mechanisms are investigated by comparing observations of Li abundances in stellar atmospheres to models of stellar…
Helioseismic observations have revealed many properties of the Sun: the depth and the helium abundance of the convection zone, the sound-speed and the density profiles in the solar interior. Those constraints have been used to judge the…
We study a process of slow mixing in stars with convective envelopes, which is driven by the settling of cool downward plumes below the base of the convection zone. If a small fraction (of order $10^{-7}$) of the material cooled at the…
Convective-core overshoot mixing is a significant uncertainty in stellar evolution. Because numerical simulations and turbulent convection models predict exponentially decreasing radial rms turbulent velocity, a popular treatment of the…
We reconsider the role of pre-main sequence (pre-MS) Li depletion on the basis of new observational and theoretical evidence: i) new observations of Halpha emissions in young clusters show that mass accretion could be continuing till the…
On the long nuclear time scale of stellar main-sequence evolution, even weak mixing processes can become relevant for redistributing chemical species in a star. We investigate a process of "differential heating," which occurs when a…
Current standard solar models neither account properly for the photospheric lithium abundance nor reproduce the inferred solar sound speed profile. Diffusive overshooting at the base of the solar convective envelope has previously been…
Recent hydrodynamical simulations of convection in a solar-like model suggest that penetrative convective flows at the boundary of the convective envelope modify the thermal background in the overshooting layer. Based on these results, we…
Convective overshoot mixing is a critical ingredient of stellar structure models, but is treated in most cases by ad hoc extensions of the mixing-length theory for convection. Advanced theories which are both more physical and numerically…
Mixing in the convective core is quite uncertain in core helium burning stars. In order to explore the overshooting mixing beyond the convective core, we incorporated the $k$-$\omega$ proposed by Li (2012, 2017) into MESA, and investigated…
The convective overshoot mixing plays an important role in stellar structure and evolution. However, the overshoot mixing is a long standing problem. The uncertainty of the overshoot mixing is one of the most uncertain factors in stellar…
The prediction of the PLANCK-constrained primordial lithium abundance in the Universe is in discordance with the observed Li abundances in warm Population II dwarf and subgiant stars. Among the physically best motivated ideas, it has been…