SIMBAD references

UBV photoelectric light curves of the eclipsing variable DK Cygni, were obtained during four nights in September, 1986. They are compared with previous light curves of the system. The primary minimum shows a transit, whereas the secondary minimum, shows an occultation. The star may be classified as an A-type W UMa system. Two salient points arise from the light curves: First, the maximum after the secondary minimum is increasing in brightness and second, the depth of the secondary minimum is varying as compared with the primary minimum. These changing patterns of surface brightness may be due to irregulality in mass transfer that takes place between the components. The parabolic trend of the (O-C) diagram reveals that the orbital period increases linearly at the rate of 9.76x10^–12 days/cycle.