Tidal tails in the disintegrating open cluster NGC 752

TL;DR

This study uses Gaia data and a new membership algorithm to discover and analyze tidal tails of the open cluster NGC 752, revealing its disintegration and mass-loss history.

Contribution

It reports the first detection of tidal tails in NGC 752 and characterizes its mass function and disintegration process using Gaia data and stellar isochrones.

Findings

Discovered tidal tails extending 35 pc from NGC 752

Mass function slope indicates mass segregation and disintegration

Estimated that NGC 752 lost over 95% of its initial mass

Abstract

We utilize the robust membership determination algorithm, ML-MOC, on the precise astrometric and deep photometric data from Gaia Early Data Release 3 within a region of radius 5$^{\circ}$ around the center of the intermediate-age galactic open cluster NGC 752 to identify its member stars. We report the discovery of the tidal tails of NGC 752, extending out to $\sim$35 pc on either side of its denser central region and following the cluster orbit. From comparison with PARSEC stellar isochrones, we obtain the mass function of the cluster with a slope, $\chi=-1.26\pm0.07$. The high negative value of $\chi$ is indicative of a disintegrating cluster undergoing mass-segregation. $\chi$ is more negative in the intra-tidal regions as compared to the outskirts of NGC 752. We estimate a present day mass of the cluster, M$\rm_{C}=297\pm10$ M$_{\odot}$. Through mass-loss due to stellar evolution and tidal interactions, we further estimate that NGC 752 has lost nearly 95.2-98.5 % of its initial mass, $\rm M_{i}~=~0.64~-2~\times~10^{4}~M_{\odot}$.