SEARCH FOR 2ND OVERTONE MODE CEPHEIDS IN THE MAGELLANIC CLOUDS - I - STUDY OF 3 CANDIDATES IN THE SMALL-MAGELLANIC-CLOUD

Accurate CCD observations of three Cepheids in the SMC were made with the purpose of confirming their nature of second overtone mode Cepheid s. The stars were suspected pulsating in the second overtone mode owin g to the unusual light curve and short period reported by Payne-Gaposc hkin & Gaposchkin (1966). The analysis of the new data shows that for two stars the previous periods are wrong; and in the three cases the n ew light curves are normal. According to the new observations, HV 1353 is a fundamental mode pulsator with small amplitude, and HV 1777 and HV 1778 are first overtone mode pulsators. Also the star HV 1763, whos e nature was unknown, was observed in the field of HV 1777. The new da ta show that it is a first overtone mode Cepheid with P = 2.(d)117.