Bibcode
Montalbán, J.; Schatzman, E.
Bibliographical reference
Astronomy and Astrophysics, v.354, p.943-959 (2000)
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2
2000
Journal
Citations
85
Refereed citations
72
Description
In this paper we deal with the problem of the generation of internal
waves at the bottom of convective zone in solar-type stars, and with the
transport process linked to the non-adiabatic propagation of these waves
through the stable radiative region. The main improvement with respect
to the previous papers in this series comes from the convection
treatment chosen in order to describe the perturbations exciting the
internal waves at the boundary convective/stratified zones. We consider
a model of convective transport by plumes as described by Rieutord &
Zahn (1995), taking into account the presence of overshooting as
modelled by Zahn (1991). A model of convective transport by plumes
implies that it is no longer necessary to introduce an ad hoc parameter
to emulate the consequences of asymmetric downward and upward flows, as
was the case when a classical description of the convection was adopted.
The velocity field produced in the stellar interior by gravity waves
provides a diffusion coefficient. The predictions of this transport
process for light element abundances in low-mass stars reproduce the
observational features of lithium abundance: its dependence on mass and
age. Furthermore, a phenomenological treatment of the interaction
rotation/overshooting based on numerical simulations of the penetrative
convection with and without rotation (Julien et al. 1996a, 1997a)
provides a more or less efficient mixing process depending on the
rotational state of the star and reproduces the observed ``correlation''
between lithium abundance and rotational velocity and the scatter of
lithium abundance in stars of the same age, mass and chemical
composition. The dependence of the diffusion coefficient on the depth
below the convective zone is tested by comparing the prediction for Be
abundance with the available observations. The results are also in good
agreement, but the uncertainties in the observations are too large.