The metal content of planet hosting stars is an important ingredient which may affect the formation and evolution of planetary systems. Accurate stellar abundances require the determinations of reliable physical parameters, namely the effective temperature, surface gravity, microturbulent velocity, and metallicity. This work presents the homogeneous derivation of such parameters for a large sample of stars hosting planets (N=117), as well as a control sample of disk stars not known to harbor giant, closely orbiting planets (N=145). Stellar parameters and iron abundances are derived from an automated analysis technique developed for this work. As previously found in the literature, the results in this study indicate that the metallicity distribution of planet hosting stars is more metal-rich by ∼0.15 dex when compared to the control sample stars. A segregation of the sample according to planet mass indicates that the metallicity distribution of stars hosting only Neptunian-mass planets (with no Jovian-mass planets) tends to be more metal-poor in comparison with that obtained for stars hosting a closely orbiting Jovian planet. The significance of this difference in metallicity arises from a homogeneous analysis of samples of FGK dwarfs which do not include the cooler and more problematic M dwarfs. This result would indicate that there is a possible link between planet mass and metallicity such that metallicity plays a role in setting the mass of the most massive planet. Further confirmation, however, must await larger samples.1 Based on observations made with the 2.2 m telescope at the European Southern Observatory (La Silla, Chile), under the agreement ESO-Observatório Nacional/MCT.

We report the recovery of a spectroscopic event in h Carinae in 1997/1998 after a prediction by Damineli in 1996. A true periodicity with days (0.2% uncertainty) is obtained. The line intensities and the P = 2020 ‫ע‬ 5 radial velocity curve display a phase-locked behavior, implying that the energy and dynamics of the event repeat from cycle to cycle. This rules out S Doradus oscillation or multiple shell ejection by an unstable star as the explanation of the spectroscopic events. A colliding-wind binary scenario is supported by our spectroscopic data and by X-ray observations. Although deviations from a simple case exist around periastron, intensive monitoring during the next event (mid-2003) will be crucial to our understanding of the system.

Context. B[e] supergiants are surrounded by large amounts of hydrogen neutral material, traced by the emission in the optical [Oi] lines. This neutral material is most plausibly located within their dense, cool circumstellar disks, which are formed from the (probably non-spherically symmetric) wind material released by the star. Neither the formation mechanism nor the resulting structure and internal kinematics of these disks (or disk-like outflows) are well known. However, rapid rotation, lifting the material from the equatorial surface region, seems to play a fundamental role. Aims. The B[e] supergiant LHA 115-S 65 (in short: S 65) in the Small Magellanic Cloud is one of the two most rapidly rotating B[e] stars known. Its almost edge-on orientation allows a detailed kinematical study of its optically thin forbidden emission lines. With a focus on the rather strong [Oi] lines, we intend to test the two plausible disk scenarios: the outflowing and the Keplerian rotating disk. Methods. Based on high-and low-resolution optical spectra, we investigate the density and temperature structure in those disk regions that are traced by the [Oi] emission to constrain the disk sizes and mass fluxes needed to explain the observed [Oi] line luminosities. In addition, we compute the emerging line profiles expected for either an outflowing disk or a Keplerian rotating disk, which can directly be compared to the observed profiles. Results. Both disk scenarios deliver reasonably good fits to the line luminosities and profiles of the [Oi] lines. Nevertheless, the Keplerian disk model seems to be the more realistic one, because it also agrees with the kinematics derived from the large number of additional lines in the spectrum. As additional support for the presence of a high-density, gaseous disk, the spectrum shows two very intense and clearly double-peaked [Caii] lines. We discuss a possible disk-formation mechanism, and similarities between S 65 and the group of Luminous Blue Variables.