Light-curve and period changes of AB-Andromedae

Abstract

New photoelectric observations of AB And obtained between 1989 and 1992 have been used, together with all available light curves from the literature, to study the light-curve variation of the system and its probable connection with the orbital period variation. A long-term brightness variation in the light levels is detected. The maximum brightness occurred in 1970 (±3 yr). A period study based on all available times of minimum light (of which 22 are newly determined) reveals that the photometric period of the system oscillates around a mean value (P 0 ≃0.331890 d) with an oscillation period of ≃88.0±0.2 yr and a half-amplitude of 0.00000376 d