UBVI CCD Photometry of the Old Open Cluster NGC 1193

TL;DR

This study provides UBVI photometry of the old open cluster NGC 1193, determining its reddening, metallicity, distance, and age through analysis of color-magnitude and color-color diagrams.

Contribution

It offers new photometric data and detailed parameter estimates for NGC 1193, including discovery of blue stragglers and refined measurements of its properties.

Findings

Reddening E(B-V)=0.19 +/- 0.04

Metallicity [Fe/H]=-0.45 +/- 0.12

Age log t=9.7 +/- 0.1

Abstract

We present UBVI photometry of the old open cluster NGC 1193. Color-magnitude diagrams (CMDs) of this cluster show a well defined main sequence and a sparse red giant branch. For the inner region of r<50 arcsec, three blue straggler candidates are newly found in addition to the objects Kaluzny (1988) already found. The color-color diagrams show that the reddening value toward NGC 1193 is E(B-V) =0.19 +/- 0.04. From the ultraviolet excess measurement, we derived the metallicity to be [Fe/H]=-0.45 +/- 0.12. A distance modulus of (m-M)_0 =13.3 +/- 0.15 is obtained from zero age main sequence fitting with the empirically calibrated Hyades isochrone of Pinsonneault et al. (2004). CMD comparison with the Padova isochrones by Bertelli et al. (1994) gives an age of log t =9.7 +/- 0.1.