Improved fundamental parameters and LTE abundances of the CoRoT solar-type pulsator HD 49933^*,**

¹ Institut für Astronomie, Universität Wien, Türkenschanzstrasse 17, 1180 Wien, Austria e-mail: [ryabchik;fossati]@astro.univie.ac.at;denis.shulyak@gmail.com
² Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 119017 Moscow, Russia e-mail: ryabchik@inasan.ru

Received: 18 February 2009
Accepted: 7 May 2009

Abstract

Aims. The knowledge of accurate stellar parameters is a key stone in several fields of stellar astrophysics, such as asteroseismology and stellar evolution. Although the parameters can be derived both from spectroscopy and multicolour photometry, the results obtained are sometimes affected by systematic uncertainties. In this paper, we present a self-consistent spectral analysis of the solar-type star HD 49933, which is a primary target for the CoRoT satellite.

Methods. We used high-resolution and high signal-to-noise ratio spectra to carry out a consistent parameter estimation abundance analysis of HD 49933. The llmodels code was employed for model atmosphere calculations, while synth3 and width9 codes were used for line profile calculation and LTE abundance analysis.

Results. We provide a detailed description of the methodology adopted to derive the fundamental parameters and the abundances. Although the parameters obtained differ from the ones previously derived by other authors, we show that only the set obtained in this work is able to fit the observed spectrum accurately. In particular, the surface gravity was adjusted to fit pressure-sensitive spectral features.

Conclusions. We confirm the importance of a consistent analysis of relevant spectroscopic features, application of advanced model atmospheres, and the use of up-to-date atomic line data for the determination of stellar parameters. These results are crucial for further studies, e.g., detailed theoretical modelling of the observed pulsation frequencies.