A CCD Search for Variable Stars of Spectral Type B in the Northern Hemisphere Open Clusters. VII. NGC 1502

TL;DR

This study identifies and characterizes eight variable stars in the young open cluster NGC 1502, including eclipsing binaries, a beta Cep star, and others, providing new insights into stellar variability and cluster properties.

Contribution

First detailed variability survey of NGC 1502 identifying new variable stars and confirming suspected variables, with comprehensive photometry and cluster parameter analysis.

Findings

Eight variable stars discovered, including eclipsing binaries and a beta Cep star.

Cluster parameters estimated with a 10-Myr isochrone fitting at 1 kpc distance.

Additional photometry data provided for cluster stars.

Abstract

We present results of variability search in the field of the young open cluster NGC 1502. Eight variable stars were discovered. Of six other stars in the observed field that were suspected for variability, we confirm variability of two, including one beta Cep star, NGC 1502-26. The remaining four suspects were found to be constant in our photometry. In addition, UBVI photometry of the well-known massive eclipsing binary SZ Cam was obtained. The new variable stars include: two eclipsing binaries of which one is a relatively bright detached system with an EA-type light curve, an alpha2 CVn-type variable, an SPB candidate, a field RR Lyrae star and three other variables showing variability of unknown origin. The variability of two of them is probably related to their emission in Halpha, which has been measured by means of the alpha index obtained for 57 stars brighter than V=16 mag in the central part of the observed field. Four other non-variable stars with emission in Halpha were also found. Additionally, we provide VI photometry for stars down to V=17 mag and UB photometry for about 50 brightest stars in the observed field. We also show that the 10-Myr isochrone fits very well the observed color-magnitude diagram if a distance of 1 kpc and mean reddening, E(V-I)=0.9 mag, are adopted.