The disintegrating old open cluster Czernik 3

TL;DR

This study provides a comprehensive analysis of Czernik 3, revealing its disintegrating state, elongated morphology, and dynamical properties, suggesting it is a loosely bound cluster undergoing external tidal disruption.

Contribution

First detailed multi-data analysis of Czernik 3 revealing its disintegrating, elongated, and dynamically relaxed state with new estimates of its physical parameters.

Findings

Cluster is highly elongated with fractal star distribution.

Czernik 3 is a loosely bound, disintegrating cluster influenced by external tides.

Cluster shows signs of mass segregation and is dynamically relaxed.

Abstract

We have performed a detailed analysis of the Czernik 3 (Cz3) open cluster by using deep near-infrared photometry taken with TIRCAM2 on 3.6m Devasthal optical telescope along with the recently available high quality proper motion data from the {\it Gaia} DR2 and deep photometric data from Pan-STARRS1. The cluster has a highly elongated morphology with fractal distribution of stars. The core and cluster radii of the cluster are estimated as 0.5 pc and 1.2 pc, respectively. We have identified 45 stars as cluster members using the {\it Gaia} proper motion data. The distance and age of the cluster are found to be $3.5\pm0.9$ kpc and $0.9^{+0.3}_{-0.1}$ Gyr, respectively. The slope of the mass function $`\Gamma'$ in the cluster region, in the mass range $\sim$0.95$<$M/M$_\odot$$<$2.2, is found to be $-1.01\pm0.43$. The cluster shows the signatures of mass-segregation and is dynamically relaxed (dynamical age=10 Myr). This along with its small size, big tidal radius, low density/large separation of stars, and elongated and distorted morphology, indicate that the Cz3 is a loosely bound disintegrating cluster under the influence of external tidal interactions.