Impact of the physical processes in the modeling of HD 49933

Free access article

Issue		A&A Volume 506, Number 1, October IV 2009 The CoRoT space mission: early results


Page(s)		175 - 181
Section		Stellar structure and evolution
DOI		http://dx.doi.org/10.1051/0004-6361/200911947
Published online		15 July 2009

A&A 506, 175-181 (2009)
DOI: 10.1051/0004-6361/200911947

Impact of the physical processes in the modeling of HD 49933

L. Piau¹, S. Turck-Chièze¹, V. Duez¹, and R. F. Stein²

¹ CEA-Saclay, DSM/IRFU/SAp, L'Orme des merisiers, Bâtiment 709, 91191 Gif-sur-Yvette, France
e-mail: laurent.piau@cea.fr
² Michigan State University, Department of Physics & Astronomy East Lansing, MI 48824-2320, USA

Received 25 February 2009 / Accepted 25 June 2009

Abstract
Context. On its asteroseismic side, the initial run of CoRoT was partly devoted to the solar like star HD 49933. The eigenmodes of this F dwarf have been observed with unprecedented accuracy.
Aims. We investigate quantitatively the impact of changes in the modeling parameters like mass and composition. More importantly we investigate how a sophisticated physics affects the seismological picture of HD 49933. We consider the effects of diffusion, rotation and the changes in convection efficiency.
Methods. We use the CESAM stellar evolution code coupled to the ADIPLS adiabatic pulsation package to build secular models and their associated oscillation frequencies. We also exploited the hydrodynamical code STAGGER to perform surface convection calculations. The seismic variables used in this work are: the large frequency separation, the derivative of the surface phase shift, and the eigenfrequencies $\nu_{\ell=0,n=14}$ and $\nu_{\ell=0,n=27}$ .
Results. Mass and uncertainties on the composition have much larger impacts on the seismic variables we consider than the rotation. The derivative of the surface phase shift is a promising variable for the determination of the helium content. The seismological variables of HD 49933 are sensitive to the assumed solar composition and also to the presence of diffusion in the models.

Key words: stars: late-type -- stars: oscillations -- stars: interiors -- stars: rotation -- convection

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