Spectroscopic metallicities for planet-host stars: Extending the samples

¹ Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal e-mail: Nuno.Santos@oal.ul.pt
² Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
³ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain

Received: 17 February 2005
Accepted: 23 March 2005

Abstract

We present stellar parameters and metallicities for 29 planet-host stars, as well as for a large volume-limited sample of 53 stars not known to be orbited by any planetary-mass companion. These stars add to the results presented in our previous series of papers, providing two large and uniform samples of 119 planet-hosts and 94 “single” stars with accurate stellar parameters and [Fe/H] estimates. The analysis of the results further confirms that stars with planets are metal-rich when compared with average field dwarfs. Important biases that may compromise future studies are also discussed. Finally, we compare the metallicity distributions for single planet-hosts and planet-hosts in multiple stellar systems. The results show that a small difference cannot be excluded, in the sense that the latter sample is slighly overmetallic. However, more data are needed to confirm this correlation.