Metallicities for 13 nearby open clusters from high-resolution spectroscopy of dwarf and giant stars

Abstract

We present a study of accurate stellar parameters and iron abundances for 39 giants and 16 dwarfs in the 13 open clusters IC 2714, IC 4651, IC 4756, NGC 2360, NGC 2423, NGC 2447 (M 93), NGC 2539, NGC 2682 (M 67), NGC 3114, NGC 3680, NGC 4349, NGC 5822, NGC 6633. The analysis was done using a set of high-resolution and high-S/N spectra obtained with the UVES spectrograph (VLT). These clusters are currently being searched for planets using precise radial velocities. For all the clusters, the derived average metallicities are close to solar. Interestingly, the values derived seem to depend on the line-list used. This dependence and its implications for the study of chemical abundances in giants stars are discussed. We show that a careful choice of the lines may be crucial for the derivation of metallicities for giant stars on the same metallicity scale as those derived for dwarfs. Finally, we discuss the implications of the derived abundances for the metallicity- and mass-giant planet correlation. We conclude that a good knowledge of the two parameters is necessary to correctly disentangle their influence on the formation of giant planets. © 2008 ESO.