* Astronomy

Title: Marginally low mass ratio close binary system V1191 Cyg
Authors: B. Ulas, B. Kalomeni, V. Keskin, O. Kose, K. Yakut

In this study, we present photometric and spectroscopic variations of the extremely small mass ratio (q\simeq 0.1) late-type contact binary system V1191 Cyg. The parameters for the hot and cooler companions have been determined as M_h = 0.13 (1) solar masses, M_c = 1.29 (8) solar masses, R_h = 0.52 (15) solar radii, R_c = 1.31 (18) solar radii, L_h = 0.46 (25) solar luminance L_c = 2.71 (80) solar luminance, the separation of the components is a= 2.20(8) solar radii 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) x 10^{-6} days/yr that reveals a very high mass transfer rate of \frac{dM}{dt}=2.0(4) x 10^{-7} solar masses/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.

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