EDP Sciences
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Volume 373, Number 3, July III 2001
Page(s) 1019 - 1031
Section Formation and evolution of planetary systems
DOI http://dx.doi.org/10.1051/0004-6361:20010648

A&A 373, 1019-1031 (2001)
DOI: 10.1051/0004-6361:20010648

The metal-rich nature of stars with planets

N. C. Santos1, G. Israelian2 and M. Mayor1

1  Observatoire de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland
2  Instituto de Astrofisica de Canarias, 38205 La Laguna, Tenerife, Spain

(Received 13 March 2001 / Accepted 3 May 2001)

With the goal of confirming the metallicity "excess" present in stars with planetary-mass companions, we present in this paper a high-precision spectroscopic study of a sample of dwarfs included in the CORALIE extrasolar planet survey. The targets were chosen according to the basic criteria that 1) they formed part of a limited volume and 2) they did not present the signature of a planetary host companion. A few stars with planets were also observed and analysed; namely, HD 6434 , HD 13445 (Gl 86), HD 16141 , HD 17051 ($\iota$ Hor), HD 19994 , HD 22049 ($\epsilon$ Eri), HD 28185 , HD 38529 , HD 52265 , HD 190228 , HD 210277 and HD 217107 . For some of these objects there had been no previous spectroscopic studies. The spectroscopic analysis was done using the same technique as in previous work on the metallicity of stars with planets, thereby permitting a direct comparison of the results. The work described in this paper thus represents the first uniform and unbiased comparison between stars with and without planetary-mass companions in a volume-limited sample. The results show that 1) stars with planets are significantly metal-rich, and 2) that the source of the metallicity is most probably "primordial" . The results presented here may impose serious constraints on planetary system formation and evolution models.

Key words: stars: abundances -- stars: chemically peculiar -- planetary systems

Offprint request: N. C. Santos, Nuno.Santos@obs.unige.ch

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