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. Mayor11 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)
Abstract
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
(
Hor),
HD 19994
,
HD 22049
(
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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