Open clusters as tracers of the evolution of the abundance gradients

People involved at OAB: Bragaglia, Carretta, Cignoni, Pancino, Tosi

Figure: The radial metallicity gradient as defined by the open clusters. (a) We show the clusters in the Dias et al. (2002) catalogue, with the three clusters analysed in Andreuzzi et al. (2010: Be 20, Be 66, and To 2) indicated by filled, red symbols. (b) We show here only clusters for which [Fe/H] has been derived using high resolution spectroscopy. The BOCCE clusters are indicated by filled symbols, with the last three clusters analysed shown with larger, filled symbols.

Open clusters are very useful tracers of the properties of the Galactic disk. In the context of the BOCCE project (the Bologna Open Cluster Chemical Evolution project) Bragaglia and Tosi continued the analysis of photometric data collected at ESO and TNG (Andreuzzi et al. 2010) or LBT (paper in preparation); see Fig.  and the web page. Bragaglia, Carretta and Tosi continued the study of SARG@TNG spectra of clusters in collaboration with Gratton (INAF-OAPd). Bragaglia and Carretta, in collaboration with Sneden (Univ. Austin), Gratton and Lucatello (INAF-OAPd) obtained and analysed Hydra@WIYN spectra of NGC6791, to see whether the Na-O anticorrelation is really seen exclusively in globular clusters. Bragaglia and Pancino joined the working group on open clusters and associations, which is part of the GREAT network and participated in a successful FP7 ITN grant request (PI N. Walton, Cambridge).

This research is in collaboration with Cignoni (Univ. Bologna), Gratton, Lucatello (INAF-Padova Obs.), Marconi (ESO, Chile), Andreuzzi (INAF-Roma Obs., TNG), Beccari (ESO, Garching), Sneden (Univ. Texas, USA).

A set of 13 open clusters was observed with FOCES@CAHA2.2 m and UVES@VLT for abundance analysis. The first paper, concerning Cr 110, M 67, NGC 2099, NGC 2420, and NGC 7789, has been submitted and published (Pancino et al. 2010). A second paper focussed on Berkeley 32, NGC 752, Hyades, and Praesepe is in preparation (Carrera et al., in preparation).

This research is in collaboration with C. Gallart and R. Carrera (IAC Tenerife, Spain).