Wide-Field CCD Photometry around Nine Open Clusters

Abstract

In this paper we study the evolution of the core and corona of nine open clusters using the projected radial density profiles derived from homogeneous CCD photometric data obtained with the 105 cm Kiso Schmidt telescope. The age and galactocentric distance of the target clusters vary from 16 to 2000 Myr and 9 to 10.8 kpc, respectively. Barring Be 62, which is a young open cluster, other clusters show a uniform reddening across the cluster region. The reddening in Be 62 varies from E(B À V ) min ¼ 0:70 mag to E(B À V ) max ¼ 1:00 mag. The coronae of six of the clusters in the present sample are found to be elongated; however, on the basis of the present sample it is not possible to establish any correlation between the age and shape of the core. The elongated core in the case of the young cluster Be 62 may reflect the initial conditions in the parental molecular cloud. The other results of the present study are as follows:(1) Core radius r c and corona size r cn /cluster radius r cl are linearly correlated.(2) The r c , r cn , and r cl are linearly correlated with the number of stars in that region. (3) In the age range 10Y1000 Myr, the core and corona shrink with age. (4) We find that in the galactocentric distance range 9Y10 kpc, the core and corona/cluster extent of the clusters increase with the galactocentric distance.

Photoelectric search for peculiar stars in open clusters

“…There are some recent investigations of NGC 2323 that include photometric but no spectroscopic data (Clariá et al 1998;Sharma et al 2006;Frolov et al 2012). Clariá et al (1998) list E(B − V) = 0.23 mag for W171 which corresponds to the mean value of the cluster (Table 1).…”

Chemical Abundances in a Sample of Red Giants in the Open Cluster NGC 2420 From Apogee

“…The open cluster NGC 2420, with an age of roughly 2 Gyr, is located towards the Galactic anti-center at a Galactocentric distance of 10.78 kpc (Sharma et al 2006). Given its age, location, and metallicity, this cluster is an interesting object for studies of Galactic chemical evolution.…”

Role of Gas Dynamical Friction in the Evolution of Embedded Stellar Clusters

“…Hence it is possible that, relative segregation, between the stars / cores / clumps of various masses may occur and, some signature of this might survive, even after relaxation, in the clusters evolving out of dense gas clouds. We note that, the brown dwarfs associated with a cluster are distributed in a region much larger than what is occupied by the cluster itself (Luhman 2006;Kumar & Schmeja 2007;Kouwenhoven, Brown & Kaper 2007), and clusters do seem to have associated with them a corona of low mass stars ( (Sharma et al 2006;Luhman 2006;Kumar & Schmeja 2007;Kouwenhoven, Brown & Kaper 2007); see also Gorti & Bhatt (1996)). Such a 'core-halo' structure has been noticed for some Massive Young Clusters too (Maíz-Apellániz 2001).…”