Spectroscopic parameters for 451 stars in the HARPS GTO planet search program

Free access article

Issue		A&A Volume 487, Number 1, August III 2008


Page(s)		373 - 381
Section		Planets and planetary systems
DOI		http://dx.doi.org/10.1051/0004-6361:200809698
Published online		04 June 2008

A&A 487, 373-381 (2008)
DOI: 10.1051/0004-6361:200809698

Stellar [Fe/H] and the frequency of exo-Neptunes

S. G. Sousa^{1, 2}, N. C. Santos^{1, 3}, M. Mayor³, S. Udry³, L. Casagrande⁴, G. Israelian⁵, F. Pepe³, D. Queloz³, and M. J. P. F. G. Monteiro^{1, 2}

¹ Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
e-mail: sousasag@astro.up.pt
² Departamento de Matemática Aplicada, Faculdade de Ciências da Universidade do Porto, Portugal
³ Observatoire de Genève, 51 Ch. des Mailletes, 1290 Sauverny, Switzerland
⁴ University of Turku - Tuorla Astronomical Observatory, Väisäläntie 20, 21500 Piikkiö, Finland
⁵ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain

Received 3 March 2008 / Accepted 30 April 2008

Abstract
To understand the formation and evolution of solar-type stars in the solar neighborhood, we need to measure their stellar parameters to high accuracy. We present a catalogue of accurate stellar parameters for 451 stars that represent the HARPS Guaranteed Time Observations (GTO) "high precision" sample. Spectroscopic stellar parameters were measured using high signal-to-noise (S/N) spectra acquired with the HARPS spectrograph. The spectroscopic analysis was completed assuming LTE with a grid of Kurucz atmosphere models and the recent ARES code for measuring line equivalent widths. We show that our results agree well with those ones presented in the literature (for stars in common). We present a useful calibration for the effective temperature as a function of the index color B-V and [Fe/H]. We use our results to study the metallicity-planet correlation, namely for very low mass planets. The results presented here suggest that in contrast to their jovian couterparts, neptune-like planets do not form preferentially around metal-rich stars. The ratio of jupiter-to-neptunes is also an increasing function of stellar metallicity. These results are discussed in the context of the core-accretion model for planet formation.

Key words: methods: data analysis -- techniques: spectroscopic -- stars: fundamental parameters -- stars: planetary systems -- stars: planetary systems: formation -- Galaxy: solar neighborhood

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.