Survey for Transiting Extrasolar Planets in Stellar Systems. II. Spectrophotometry and Metallicities of Open Clusters

We present metallicity estimates for seven open clusters based onspectrophotometric indices from moderate-resolution spectroscopy. Observationsof field giants of known metallicity provide a correlation between thespectroscopic indices and the metallicity of open cluster giants. We use \chi^2analysis to fit the relation of spectrophotometric indices to metallicity infield giants. The resulting function allows an estimate of the target-clustergiants' metallicities with an error in the method of \pm0.08 dex. We derive thefollowing metallicities for the seven open clusters: NGC 1245,[m/H]=-0.14\pm0.04; NGC 2099, [m/H]=+0.05\pm0.05; NGC 2324, [m/H]=-0.06\pm0.04;NGC 2539, [m/H]=-0.04\pm0.03; NGC 2682 (M67), [m/H]=-0.05\pm0.02; NGC 6705,[m/H]=+0.14\pm0.08; NGC 6819, [m/H]=-0.07\pm0.12. These metallicity estimateswill be useful in planning future extra-solar planet transit searches sinceplanets may form more readily in metal-rich environments.Comment: 38 pages, including 12 figures. Accepted for publication in A