Open Clusters in 2MASS Photometry

Study of open clusters is important not only for learning properties of these objects but also for understanding the process of formation and evolution of stars and the Milky Way. The main goal of our project is to obtain a complete picture of individual open clusters from homogeneous data and then search for correlations between their astrophysical parameters. The near-infrared JHK photometric data from the 2-Micron All Sky Survey were used to determine new coordinates of the centres, angular sizes and radial density profiles for 849 open clusters in theMilkyWay. Additionally, age, reddening, distance, and linear sizes were also derived for 754 of them.The analysed sample contains open clusters with ages in the range from 7 Myr to 10 Gyr. The majority of these clusters are located up to 3 kpc from the Sun, less than 0.4 kpc from the Galactic Plane and 6 - 12 kpc from the Galactic Centre. The majority of clusters have core radii of about 1.5 pc and the limiting radii of the order of 10 pc. We notice that in the nearĐinfrared, open clusters seem to be greater than in optical bands. We notice that a paucity of clusters is observed in the Galactic longitude range from 140° to 200° which probably might be a real effect. This lack of clusters have been found earlier. We obtained the relation E(J-K)/E(B-V) = 0.465 which is different from predictions of the standard interstellar reddening law.

 Available data

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Last modified: Mach 6, 2012