Asteroseismic tests of element diffusion in solar type stars

¹ Université de Liège, allée du 6 Août 17, 4000 Liège, Belgium
² Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
³ Laboratoire d'Astrophysique, 14 Av. Ed. Belin, 31400 Toulouse, France e-mail: svcr@ast.obs-mip.fr

Received: 8 November 2004
Accepted: 21 February 2005

Abstract

Following the success of helioseismology, asteroseismology is now becoming a fundamental tool for penetrating the secrets of the internal structure of stars. In preparation of this new era in stellar physics, we study the effects of element diffusion on the computed frequencies of stellar oscillation modes for main-sequence solar-type stars. As the observed stars will be constrained by their atmospheric parameters, stellar models were computed with different physical inputs (whether including element diffusion or not) and iterated in order to fit the same observables (effective temperature, luminosity, surface chemical composition). The theoretical oscillation frequencies of these models were derived and compared. The results show that diffusion alters the internal structure of the models and their oscillation frequencies in a significant way. Although observational uncertainties in stellar external parameters are still important, comparisons between oscillation frequencies observed with the future space mission COROT and theoretically computed ones might provide evidence for diffusion processes in solar type stars.