Optical photometry and basic parameters of 10 unstudied open clusters

Abstract

We present BVI CCD photometry of 10 northern open clusters, Berkeley 43, Berkeley 45, Berkeley 47, NGC 6846, Berkeley 49, Berkeley 51, Berkeley 89, Berkeley 91, Tombaugh 4 and Berkeley 9, and estimate their fundamental parameters. Eight of the clusters are located in the first Galactic quadrant and two are in the second. This is the first optical photometry for eight clusters. All of them are embedded in rich Galactic fields and have large reddening towards them [E(B−V) = 1.0–2.3 mag]. There is a possibility that some of these difficult-to-study clusters may be asterisms rather than physical systems, but assuming that they are physical clusters, we find that eight of them are located beyond 2 kpc and six clusters (60 per cent of the sample) are located well above or below the Galactic plane. Seven clusters have ages 500 Myr or less and the other three are 1 Gyr or more in age. This sample of clusters has increased the optical photometry of clusters in the second half of the first Galactic quadrant, beyond 2 kpc, from 10 to 15. NGC 6846 is found to be one of the most distant clusters in this region of the Galaxy.