Search for short-period variable stars in the open cluster NGC 2301

Abstract

Time-series CCD photometric observations of an intermediate age open cluster NGC 2301 were per- formed to search for variable stars, particularly Dor stars and Sct stars. We also carried outUBVI photometry to study physical properties of variable stars in the cluster. We derived observational parameters of the cluster from UBVI photometric results. The best t of the empirical ZAMS in a color-color diagram gives a reddening value of E(B V )=0 :05 0:03. We also estimated a distance modulus of (V MV )0 =9 :6 0:1 and an age of log t =8 :4 0:1, from the ZAMS and isochrone tting in a color-magnitude diagram. Using V time-series data, we carefully examined light variations of 923 stars fainter than 10: m 0, and discovered nine short-period variable stars; two Dor candidates, ve eclipsing binaries, one Slowly Pulsating B star and one magnetic Chemically Peculiar variable candidate. Two Dor candidates with relatively short periods of around 0.3 days are located in a redder region (about 0: m 1i nB V color) than the red edge of Sct instability strip in the color-magnitude diagram.