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Description
In the framework of the study of the Galactic metallicity gradient and its time evolution, we present new high-resolution spectroscopic observations obtained with FLAMES and the fiber link to UVES at VLT of three open clusters (OCs) located within ~7kpc from the Galactic Center (GC): NGC 6192, NGC 6404, NGC 6583. We also present new orbit determination for all OCs with Galactocentric distances (R_gc_)<=8kpc and metallicity from high-resolution spectroscopy. We have derived memberships of a group of evolved stars for each clusters, obtaining a sample of 4, 4, and 2 member stars in NGC 6192, NGC 6404, and NGC 6583, respectively. Using standard LTE analysis we derived stellar parameters and abundance ratios for the iron-peak elements Fe, Ni, Cr, and for the {alpha}-elements Al, Mg, Si, Ti, Ca. We calculated the orbits of the OCs currently located within 8kpc from the GC, and discuss their implication on the present-time radial location. The average metallicities of the three clusters are all oversolar: [Fe/H]= +0.12+/-0.04 (NGC 6192), +0.11+/-0.04 (NGC 6404), +0.37+/-0.03 (NGC 6583). They are in qualitative agreement with their galactocentric distances, being all internal OCs, and thus expected to be metal richer than the solar neighborhood. The abundance ratios of the other elements over iron [X/Fe] are consistent with solar values. The clusters we have analysed, together with other OC and Cepheid data, confirm a steep gradient in the inner disk, a signature of an evolutionary rate different than in the outer disk.
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