Discovery of three optical open clusters in the Galaxy
Fecha
2004Materia
Abstract
We report the discovery of three optical open clusters in the Milky Way. Two clusters are in Scutum (Cluster 1 at = 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 ...
We report the discovery of three optical open clusters in the Milky Way. Two clusters are in Scutum (Cluster 1 at = 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 ± 5 Myr, a reddening E(B − V) = 2.18 ± 0.03 and a distance from the Sun dʘ = 1.64 ± 0.19 kpc; for Cluster 2, t = 500 ± 100 Myr, E(B − V) = 0.91 ± 0.03 and dʘ = 2.19 ± 0.21 kpc; finally for Cluster 3, t = 32−100 Myr, E(B − V) = 0.94 ± 0.03 and dʘ = 3.93 ± 0.35 kpc. Luminosity and mass functions are derived for Clusters 1 and 2 which, in turn, allow us to estimate their observed masses as 147 Mʘ and 89 M , respectively. Estimated total masses, by extrapolating the mass functions to 0.08 Mʘ , amount to 382 Mʘ and 614 Mʘ for the two clusters. Cluster 3 has an observed mass of ∼55 Mʘ. The present results indicate that further searches in the optical might still reveal new open clusters, especially in the infrared bands. ...
En
Astronomy and astrophysics. Vol. 422, no. 2 (Aug. 2004), p. 555-562
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