A CCD Search for Variable Stars of Spectral Type B in the Northern Hemisphere Open Clusters I. NGC 7128
In 1994 we started a program of looking for variable stars in young open clusters. Our main goal is finding pulsating stars of spectral type B. The equipment we use consists of a 60-cm reflecting telescope and a CCD camera. In this paper, intended as the first one in a series, we detail the equipment, describe the reductions and present results for NGC 7128. For stars with instrumental magnitudes corresponding to early B spectral types on the cluster's main-sequence, the photometric accuracy we achieved allows detection of short-period variables with amplitudes exceeding 5mmag. The results include confirmation of the variability of two and discovery of six variables in the cluster. The variables we discovered comprise two eclipsing binaries, one irregular red variable, and three small-amplitude periodic variables. No B-type pulsators are present in NGC 7128.
- Pub Date:
- April 1996
- STARS: EARLY-TYPE;
- STARS: OSCILLATIONS;
- BINARIES: ECLIPSING;
- OPEN CLUSTERS AND ASSOCIATIONS: INDIVIDUAL: NGC 7128