Deep and Wide Photometry of Two Open Clusters NGC 1245 and NGC 2506: CCD Observation and Physical Properties

TL;DR

This study presents deep VI CCD photometry of open clusters NGC 1245 and NGC 2506, deriving their physical parameters, luminosity and mass functions, and discussing dynamical evolution effects.

Contribution

It provides detailed physical parameters and mass functions for two open clusters using extensive CCD photometry and theoretical isochrone fitting, highlighting dynamical evolution impacts.

Findings

Derived cluster parameters including age, distance, and metallicity.

Presented luminosity functions reaching down to M_V=10.

Found mass function slopes slightly shallower than the solar neighborhood.

Abstract

We have conducted VI CCD photometry of the two open clusters NGC 1245 and NGC 2506 using the CFH12K CCD camera. Our photometry covers a sky area of 84'X82' and 42'X81' for the two clusters, respectively, and reaches down to V = 23. We derived the physical parameters using detailed theoretical isochrone fittings using 2 minimization. The derived cluster parameters are E(B-V) = 0.24+/-0.05 and 0.03+/-0.04, (V-M_V)_0 = 12.25+/-0.12 and 12.47+/-0.08, age(Gyr) = 1.08+/-0.09 and 2.31+/-0.16, and [Fe/H]= -0.08+/-0.06 and -0.24+/-0.06, respectively for NGC 1245 and NGC 2506, We present the luminosity functions (LFs) of the two clusters, which reach down to M_V = 10, and derive mass functions (MFs) with slopes of Gamma = -1.29 for NGC 1245 and Gamma = -1.26 for NGC 2506. The slopes are slightly shallower than that of the solar neighbourhood, implying the existence of dynamical evolution that drives the evaporation of the low-mass stars in the clusters.