We present an analysis of three southern open star clusters NGC 6067, NGC 2506 and IC 4651 using wide-field photometric and Gaia DR2 astrometric data. They are poorly studied clusters. We took advantage of the synergy between Gaia DR2 high precision astrometric measurements and ground based wide-field photometry to isolate cluster members and further study these clusters. We identify the cluster members using proper motions, parallax and colour-magnitude diagrams. Mean proper motion of the clusters in µ α cosδ and µ δ is estimated as −1.90 ± 0.01 and −2.57 ± 0.01 mas yr −1 for NGC 6067, −2.57±0.01 and 3.92±0.01 mas yr −1 for NGC 2506 and −2.41±0.01 and −5.05 ± 0.02 mas yr −1 for IC 4651. Distances are estimated as 3.01 ± 0.87, 3.88 ± 0.42 and 1.00 ± 0.08 kpc for the clusters NGC 6067, NGC 2506 and IC 4651 respectively using parallaxes taken from Gaia DR2 catalogue. Galactic orbits are determined for these clusters using Galactic potential models. We find that these clusters have circular orbits. Cluster radii are determined as 10 for NGC 6067, 12 for NGC 2506 and 11 for IC 4651. Ages of the clusters estimated by isochrones fitting are 66 ± 8 Myr, 2.09 ± 0.14 Gyr and 1.59 ± 0.14 Gyr for NGC 6067, NGC 2506 and IC 4651 respectively. Mass function slope for the entire region of cluster NGC 2506 is found to be comparable with the Salpeter value in the mass range 0.77 -1.54 M . The mass function analysis shows that the slope becomes flat when one goes from halo to core region in all the three clusters. A comparison of dynamical age with cluster's age indicates that NGC 2506 and IC 4651 are dynamically relaxed clusters.

We present a comprehensive analysis (photometric and kinematical) of the poorly studied open cluster NGC 4337 using 2MASS, WISE, APASS, and Gaia DR2 databases. By determining the membership probabilities of stars, we identified the 624 most probable members with membership probability higher than 50% by using proper motion and parallax data taken from Gaia DR2. The mean proper motion of the cluster is obtained as and μ y  = 1.49 ± 0.006 mas yr−1. We find the normal interstellar extinction toward the cluster region. The radial distribution of members provides a cluster radius of 7.′75 (5.63 pc). The estimated age of 1600 ± 180 Myr indicates that NGC 4337 is an old open cluster with a bunch of red giant stars. The overall mass function slope for main-sequence stars is found as within the mass range 0.75−2.0 , which is in fair agreement with Salpeter’s value (x = 1.35) within uncertainty. The present study demonstrates that NGC 4337 is a dynamically relaxed open cluster. Using the Galactic potential model, Galactic orbits are obtained for NGC 4337. We found that this object follows a circular path around the Galactic center. Under the kinematical analysis, we compute the apex coordinates (A, D) by using two methods: (i) the classical convergent point method and (ii) the AD-diagram method. The obtained coordinates are (A conv, D conv) = (96.°27 ± 0.°10, 13.°14 ± 0.°27) and (A ◦, D ◦) = (100.°282 ± 0.°10, 9.°577 ± 0.°323) respectively. We also computed the Velocity Ellipsoid Parameters, matrix elements (μ ij ), direction cosines (l j , m j , n j ), and the Galactic longitude of the vertex (l 2).

This paper presents a comprehensive analysis of two pairs of binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324) located in the fourth quadrant of our Galaxy. For this purpose we use different data taken from VVV survey, WISE, VPHAS, APASS, GLIMPSE along with Gaia EDR3 astrometric data. We identified 584, 429, 692 and 273 most probable cluster members with membership probability higher than $80 \%$ towards the region of clusters NGC 5617, Trumpler 22, NGC 3293 and NGC 3324. We estimated the value of $R=\frac{A_{V}}{E(B-V)}$ as ∼ 3.1 for clusters NGC 5617 and Trumpler 22, which indicates normal extinction law. The value of R ∼3.8 and ∼1.9 represent the abnormal extinction law towards the clusters NGC 3293 and NGC 3324. Our Kinematical analysis show that all these clusters have circular orbits. Ages are found to be 90 ± 10 and 12 ± 3 Myr for the cluster pairs (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324), respectively. The distances of 2.43 ± 0.08, 2.64 ± 0.07, 2.59 ± 0.1 and 2.80 ± 0.2 kpc estimated using parallax are alike to the values calculated by using the distance modulus. We have also identified 18 and 44 young stellar object candidates present in NGC 5617 and Trumpler 22, respectively. Mass function slopes are found to be in fair agreement with the Salpeter’s value. The dynamical study of these objects shows a lack of faint stars in their inner regions, which leads to the mass-segregation effect. Our study indicates that NGC 5617 and Trumpler 22 are dynamically relaxed but the other pair of clusters are not. Orbital alongwith the physical parameters show that the clusters in both pairs are physically connected.

We present a U BV I photometric study of the open clusters Berkeley 24 (Be 24) and Czernik 27 (Cz 27). The radii of the clusters are determined as 2. ′ 7 and 2. ′ 3 for Be 24 and Cz 27, respectively. We use the Gaia Data Release 2 (GDR2) catalogue to estimate the mean proper motions for the clusters. We found the mean proper motion of Be 24 as 0.35 ± 0.06 mas yr −1 and 1.20 ± 0.08 mas yr −1 in right ascension and declination for Be 24 and −0.52 ± 0.05 mas yr −1 and −1.30 ± 0.05 mas yr −1 for Cz 27. We used probable cluster members selected from proper motion data for the estimation of fundamental parameters. We infer reddenings E(B − V ) = 0.45 ± 0.05 mag and 0.15 ± 0.05 mag for the two clusters. Analysis of extinction curves towards the two clusters show that both have normal interstellar extinction laws in the optical as well as in the near-IR band. From the ultraviolet excess measurement, we derive metallicities of [Fe/H]= −0.025 ± 0.01 dex and −0.042 ± 0.01 dex for the clusters Be 24 and Cz 27, respectively. The distances, as determined from main sequence fitting, are 4.4 ± 0.5 kpc and 5.6 ± 0.2 kpc. The comparison of observed CMDs with Z = 0.01 isochrones, leads to an age of 2.0 ± 0.2 Gyr and 0.6 ± 0.1 Gyr for Be 24 and Cz 27, respectively.In addition to this, we have also studied the mass function and dynamical state of these two clusters for the first time using probable cluster members. The mass function is derived after including the corrections for data incompleteness and field star contamination. Our analysis shows that both clusters are now dynamically relaxed.

This paper presents an investigation into the four open clusters Czernik 14, Haffner 14, Haffner 17 and King 10, located near the Perseus arm of the Milky Way, using the Gaia DR2, 2MASS, WISE, APASS and Pan-STARRS1 data sets. We find normal interstellar extinction in 12 photometric bands for these clusters. Using Gaia DR2 proper motion data, the numbers of likely cluster members are found to be 225, 353, 350 and 395 for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. Radii are determined as 3.5, 3.7, 6.2 and 5.7 arcmin for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. Mean proper motions in RA and Dec. are estimated as (−0.42 ± 0.02, −0.38 ± 0.01), (−1.82 ± 0.009, 1.73 ± 0.008), (−1.17 ± 0.007, 1.88 ± 0.006) and (−2.75 ± 0.008, −2.04 ± 0.006) mas yr−1 for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. The comparison of observed colour–magnitude diagrams with solar metallicity isochrones leads to ages of 570 ± 60, 320 ± 35, 90 ± 10 and 45 ± 5 Myr for these clusters. The distances of 2.9 ± 0.1, 4.8 ± 0.4, 3.6 ± 0.1 and 3.8 ± 0.1 kpc determined using parallax are similar to the values derived by the isochrone-fitting method. Mass function slopes are found to be in good agreement with the Salpeter value. The total masses are derived as 348, 595, 763 and 1088 M⊙ for Czernik 14, Haffner 14, Haffner 17 and King 10, respectively. Evidence for the existence of a mass-segregation effect is observed in each cluster. Using the Galactic potential model, Galactic orbits are derived for the clusters. It is found that all four clusters follow a circular path around the Galactic Centre.