Near-Infrared Photometric Study of the Old Open Cluster Trumpler 5

TL;DR

This study uses near-infrared photometry from 2MASS data to determine the distance, reddening, metallicity, and age of the old open cluster Trumpler 5, confirming its properties and location in the Galaxy.

Contribution

First near-infrared photometric analysis of Trumpler 5 providing updated cluster parameters and confirming its old age and metallicity.

Findings

Distance to Tr 5 is 3.1 kpc.

Reddening E(B-V) is 0.64.

Age is approximately 2.8 Gyr.

Abstract

We present JHK near-infrared photometric study for the old open cluster (OC) Trumpler 5 (Tr 5), based on the 2MASS data. From the color-magnitude diagrams of Tr 5, we have located the position of the red giant clump (RGC) stars, and used the mean magnitude of the RGC stars in K-band to estimate the distance to Tr 5, d = 3.1 +/- 0.1 kpc ((m-M)_0 = 12.46 +/- 0.04). From fitting the theoretical isochrones of Padova group, we have estimated the reddening, metallicity, and age : E(B-V) = 0.64 +/- 0.05, [Fe/H] = -0.4 +/- 0.1 dex, and t =2.8 +/- 0.2 Gyr (log t=9.45 +/- 0.04), respectively. These parameters generally agree well with those obtained from the previous studies on Tr 5 and confirms that this cluster is an old OC with metallicity being metal-poorer than solar abundance, located in the anti-Galactic center region.