33rd International Physics Congress of the Turkish-Physical-Society (TPS), Bodrum, Turkey, 6 - 10 September 2017, vol.1935
Orbital period variations of two contact binaries DF Hya and WZ And are analyzed with the least-squares method by using all available minima times. It is shown that the period variations of these systems are due mainly to the LightTime Effect (LITE) due originates from gravitational influence of a third body. New LITE elements such as, orbital periods and minimum masses of possibility third bodies are given.