Membership Probability via Control Field Colour-Magnitude Decontamination

TL;DR

This paper introduces a method to determine star cluster membership probabilities using control field colour-magnitude diagrams, improving the accuracy of fundamental parameter measurements for open clusters.

Contribution

The paper presents a novel decontamination technique employing 2MASS data to better distinguish cluster members from field stars in open clusters.

Findings

Decontaminated CMDs with membership probabilities for four open clusters.

Structural parameters derived from King profile fitting.

Enhanced accuracy in determining cluster physical parameters.

Abstract

The open clusters fundamental physical parameters are important tools to understand the formation and evolution of the Galactic disk and as grounding tests for star formation and evolution models. However only a small fraction of the known open clusters in the Milky Way has precise determination of distance, reddening, age, metallicity, radial velocity and proper motion. One of the major problems in determining these parameters lies on the difficulty to separate cluster members from field stars and to assign membership. We propose a decontamination method by employing 2MASS data in the encircling region of the clusters NGC1981, NGC2516, NGC6494 and M11. We present a decontaminated CMD of these objects showing the membership probabilities and structural parameters as derived from King profile fitting.