SIMBAD references

High-precision CCD photometric observations of the contact binary V680 Per were obtained in 2016. Its symmetric multi-color light curves were analyzed by using the Wilson-Devinney (2013) program. These photometric solutions suggest that V680 Per is an A-type W UMa contact binary with the mass ratio of q=0.693 and a fill-out factor of f = 18.84% with a small temperature difference of 101 K. Based on all minimum times, the O - C curve was analyzed for the first time in this study. A cyclic oscillation (A₃ = 0.00093 d, T₃ = 4.92 yr) superimposed on a secular decrease (dP/dt = -8.16 x 10^–8 d yr^–1) was identified. The continuous decrease in period is possibly a result of mass transfer from the more massive component to the less massive one, or angular momentum loss due to a magnetic stellar wind. Because of this secular decrease, it is predicted that the degree of contact will become higher, and V680 Per will evolve into a deeper overcontact binary.