A homogeneous spectroscopic analysis of host stars of transiting planets

Ammler-von Eiff, M.; Santos, N. C.; Sousa, S. G.; Fernandes, J.; Guillot, T.; Israelian, G.; Mayor, M.; Melo, C.
Referencia bibliográfica

Astronomy and Astrophysics, Volume 507, Issue 1, 2009, pp.523-530

Fecha de publicación:
11
2009
Número de autores
8
Número de autores del IAC
1
Número de citas
51
Número de citas referidas
47
Descripción
Context: The analysis of transiting extra-solar planets provides an enormous amount of information about the formation and evolution of planetary systems. A precise knowledge of the host stars is necessary to derive the planetary properties accurately. The properties of the host stars, especially their chemical composition, are also of interest in their own right. Aims: Information about planet formation is inferred by, among others, correlations between different parameters such as the orbital period and the metallicity of the host stars. The stellar properties studied should be derived as homogeneously as possible. The present work provides new, uniformly derived parameters for 13 host stars of transiting planets. Methods: Effective temperature, surface gravity, microturbulence parameter, and iron abundance were derived from spectra of both high signal-to-noise ratio and high resolution by assuming iron excitation and ionization equilibria. Results: For some stars, the new parameters differ from previous determinations, which is indicative of changes in the planetary radii. A systematic offset in the abundance scale with respect to previous assessments is found for the TrES and HAT objects. Our abundance measurements are remarkably robust in terms of the uncertainties in surface gravities. The iron abundances measured in the present work are supplemented by all previous determinations using the same analysis technique. The distribution of iron abundance then agrees well with the known metal-rich distribution of planet host stars. To facilitate future studies, the spectroscopic results of the current work are supplemented by the findings for other host stars of transiting planets, for a total dataset of 50 objects. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Based in part on observations made at Observatoire de Haute Provence (CNRS), France. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 080.C-0661.
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Recientemente se han llevado a cabo varios análisis espectroscópicos de estrellas con planetas. Uno de los resultados más relevantes ha sido descubrir que las estrellas con planetas son en promedio más metálicas que las estrellas del mismo tipo espectral sin planetas conocidos (Santos, Israelian & Mayor 2001, A&A, 373, 1019; 2004, A&A, 415, 1153)
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