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

摘要

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