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HARPS GTO Catalogue of spectroscopic stellar parameters; Stellar metallicity and the frequency of exo-Neptunes
Oral comunication

S. G. Sousa, N. C. Santos, M. Mayor, S. Udry, L. Casagrande, G. Israelian, F. Pepe, D. Queloz, M. J. P. F. G. Monteiro

To understand the formation and evolution of solar type stars in the solar neighborhood we need to know their stellar parameters with high accuracy. We present a catalogue with accurate stellar parameters for the 451 stars that compose the HARPS Guaranteed Time Observations (GTO) ``high precision'' sample. The spectroscopic stellar parameters were obtained using a set of high S/N spectra obtained with the HARPS spectrograph. The spectroscopic analysis was done in LTE using a grid of Kurucz atmosphere models and the recent ARES code to measure line equivalent widths. It will be also presented a description of the ARES code, and shown that the results are in very good agreement with the ones presented in other works found in the literature (for stars in common). A useful calibration is also presented for the effective temperature as a function of the index color B-V and [Fe/H].Finally we study the metallicity-planet correlation, namely for very low mass planets. The results presented suggests that contrarily to their Jovian counterparts, Neptune-like planets do not form preferentially around metal-rich stars. These results are discussed in the context of the core-accretion model for planet formation.

XVIII Encontro Nacional de Astronomia e Astrofísica
Évora, Portugal
2008 September

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia