Period Studies of Close Binaries, AO Cam and AW Cam

Abstract

Photoelectric observations of close binary stars, AO Cam and AW Cam, were made during the 1984 observing season with the 61cm reflector at the Sobaeksan Observatory. One time of primary minimum for AO Cam and three primary epochs for AW Cam were derived from the observation of these two system. Times of minimum light of these two binaries collected from literature were analyzed with a least square fitting method. New improved light elements for AO Cam and AW Cam were determined. The orbital period of AO Cam had been constant from October, 1980(JD 2444520) to February, 1985(JD 2446107). However, one secondary time of minimum(JD 2447864.7879) of AO Cam published recently by Mullis and Faulkner(1991) shows large deviation of about 4.6 minutes (0.d0032) from the one predicted by our new light elements. Future observations of times of minima for this system are needed to test this period change. The orbital period of AW Cam has been constant as P = 0d77134645 for about sixty years from the early 1930's to the present.