In this study, we present long term photometric variations of the close binary system astrobj{GO Cyg}. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe. The physical
parameters of the system are $M_1 = 3.0pm0.2 M_{odot}$, $M_2 = 1.3 pm 0.1 M_{odot}$, $R_1 = 2.50pm 0.12 R_{odot}$, $R_2 = 1.75 pm 0.09 R_{odot}$, $L_1 = 64pm 9 L_{odot}$, $L_2 = 4.9 pm 0.7 L_{odot}$, and $a = 5.5 pm 0.3 R_{odot}$. Our results show that astrobj{GO Cyg} is the most massive system near contact binary (NCB). Analysis of times of the minima shows a sinusoidal variation with a period of $92.3pm0.5$ years due to a third body whose mass is less than 2.3$M_{odot}$. Finally a period variation rate of $-1.4times10^{-9}$ d/yr has been determined using all available light curves.
In this study, we present photometric and spectroscopic variations of the extremely small mass ratio ($qsimeq 0.1$) late-type contact binary system astrobj{V1191 Cyg}. The parameters for the hot and cooler companions have been determined as $M_textrm
{h}$ = 0.13 (1) $M_{odot}$, $M_textrm{c}$ = 1.29 (8) $M_{odot}$, $R_textrm{h}$ = 0.52 (15) $R_{odot}$, $R_textrm{c}$ = 1.31 (18) $R_{odot}$, $L_textrm{h}$ = 0.46 (25) $L_{odot}$, $L_textrm{c}$ = 2.71 (80) $L_{odot}$, the separation of the components is $a$= 2.20(8) $R_{odot}$ and the distance of the system is estimated as 278(31) pc. Analyses of the times of minima indicates a period increase of $frac{dP}{dt}=1.3(1)times 10^{-6}$ days/yr that reveals a very high mass transfer rate of $frac{dM}{dt}=2.0(4)times 10^{-7}$$M_{odot}$/yr from the less massive component to the more massive one. New observations show that the depths of the minima of the light curve have been interchanged.
