2004A&A...422..555B

We report the discovery of three optical open clusters in the Milky Way. Two clusters are in Scutum (Cluster 1 at l=18.44° and b=-0.42°, and Cluster 2 at l=19.60° and b=-1.02°), thus projected not far from the Galactic center direction, and the other is in Canis Major (Cluster 3 at l=235.61° and b=-4.10°), near the anti-center direction. Cluster 3 is less populous than Clusters 1 and 2, but presents evidence of being a physical system. The objects were found optically by inspecting maps obtained from the Guide Star Catalogue and images from the Digitized Sky Survey. No previous identification of a cluster has been reported in any of these areas so far. The analysis was carried out with 2MASS photometry in J and H. For Cluster 1 we derive an age of t=25±5Myr, a reddening E(B-V)=2.18±0.03 and a distance from the Sun d_☉=1.64±0.19kpc; for Cluster 2, t=500±100Myr, E(B-V)=0.91±0.03 and d_☉=2.19±0.21kpc; finally for Cluster 3, t=32-100Myr, E(B-V)=0.94±0.03 and d_☉=3.93±0.35kpc. Luminosity and mass functions are derived for Clusters 1 and 2 which, in turn, allow us to estimate their observed masses as 147M_☉ and 89M_☉, respectively. Estimated total masses, by extrapolating the mass functions to 0.08M_☉, amount to 382M_☉ and 614M_☉ for the two clusters. Cluster 3 has an observed mass of ∼55M_☉. The present results indicate that further searches in the optical might still reveal new open clusters, especially in the infrared bands.