Atomic diffusion in star models of type earlier than G

Département Cassini, UMR CNRS 6529, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France

Corresponding author: P. Morel, Pierre.Morel@obs-nice.fr

Received: 7 February 2002
Accepted: 15 May 2002

Abstract

We introduce the mixing resulting from the radiative diffusivity associated with the radiative viscosity in the calculation of stellar evolution models. We find that the radiative diffusivity significantly diminishes the efficiency of the gravitational settling in the external layers of stellar models corresponding to types earlier than ≈G. The surface abundances of chemical species predicted by the models are successfully compared with the abundances determined in members of the Hyades open cluster. Our modeling depends on an efficiency parameter, which is evaluated to a value close to unity, that we calibrate in this study.