CAOSP abstracts, Volume: 43, No.: 1, year: 2013

Abstract: We have generated synthetic light curves for a large number of combinations of three geometric elements (a mass ratio, an orbital inclination and a fill-out factor) defining the shape and amplitude of light curves of contact binary stars. The synthetic light curves were represented by trigonometric polynomials of a 10^th order. We have investigated the uniqueness of photometric mass ratio determination by searching for light curves of a similar shape, but corresponding to different geometric parameters. The analysis was done for different precision of Fourier coefficients. The uncertainty of the photometric mass ratio was found to be as large as 0.25. The uniqueness of the photometric mass ratio further deteriorates if an unknown third light is present. In such a case, the uncertainty of the photometric mass ratio reaches as much as 0.45. The reliability of a light-curve solution improves with an increasing light-curve amplitude and precision of the Fourier coefficients, which is related to the photometric precision and number of datapoints. The analysis confirms the known fact that determination of the mass ratio from light-curve solutions is reliable for totally eclipsing systems only.