A Method for Simultaneous Determination of Metallicity and Reddening of a Globular Cluster based on the $V vs. (B-R)$ Color-Magnitude Diagram

TL;DR

This paper introduces a new method to simultaneously determine the metallicity and reddening of globular clusters using their V vs. (B-R) color-magnitude diagram, analyzing the red giant branch and horizontal branch features.

Contribution

The paper presents a novel technique that allows for the concurrent estimation of metallicity and reddening from photometric data of globular clusters.

Findings

Applied to NGC7006, the method yields [Fe/H] = -1.78 ± 0.11.

Determined reddening E_{B-R} = 0.25 ± 0.02 for NGC7006.

Demonstrates the effectiveness of the method on real cluster data.

Abstract

We describe a method by which the abundance of metals and the reddening of globular clusters are simultaneously derived. The method is based on the analysis of the shape of the red giant branch and V magnitude of the horizontal branch on the V vs. (B-R) color-magnitude diagram for a cluster. The application of our technique to the photometry of the globular cluster NGC7006 yields the metallicity $[Fe/H] = - 1.78 \pm0.11$ and the reddening $E_{B-R} = 0.^{m}25 \pm0.^{m}02$.