CAOSP abstracts, Volume: 34, No.: 1, year: 2004

Abstract: Orbital period changes of the contact binary AK Her are discussed. The (O-C) diagram constructed using all available photoelectric, CCD, photographic and visual minima times including new photoelectric minima times determined from our U,B,V observations taken in 1982 and 2003, can be explained by a long-term orbital period increase modulated by a light-time effect. The period increase is caused either by a mass transfer from the less to more massive component of the binary or by a light-time effect on a very long period orbit. The low-mass third body present in the system is responsible for the 57.2-year light-time effect. A Fourier period analysis of the residuals from the fit revealed the 17.7-year period probably caused by a spot activity cycle.

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Last update: February 11, 2004