2015AJ....149..164W

Multi-color photometric data of GN Boo observed from 2010 to 2013 are presented. The intrinsic variations of the light curves are remarkable, and their phenomena are probable evidence of stronger magnetic activities on the surfaces of the components. Based on all CCD times of minimum light, a secular increase superimposed on a cyclic oscillation is found. The orbital period increases at a rate of dP/dt = +1.74x10^–7 days/yr, which can be explained by mass transfer from the less massive component to the more massive one. The period and amplitude of the cyclic variation are P = 9.5632 yr and A = 0.0046 days, respectively, which correspond to the previous published results. Using the 2010 version of the W-D code, five sets of photometric solutions were derived from our new data. The results imply that the stellar spot, the degree of fill-out, and the temperature difference ΔT between the components of GN Boo are variable. It is inferred that the magnetic activities perhaps influence the outer radius of the component, causing the temperature of the component star and the level of contact to change.