Multi-colour photometry and Gaia EDR3 astrometry of two couples of
  binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324)
  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 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\pm10 and 12\pm3 Myr for the cluster
pairs (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324), respectively. The
distances of 2.43\pm0.08, 2.64\pm0.07, 2.59\pm0.1 and 2.80\pm0.2 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.
