The Eclipsing Binary System KO Aquilae

From our observations, and other previous ones, we found the period of the KO Aql systern to be increasing by 3 X 10-8 days per period. V light observations carried out during 1965 show a secondary minimum which becomes shallower in the 1967 and 1969 observations. The solutions of the light curves obtained were possible ouly by assuming the primary minimum to be an occultation. The elements of the system have been deduced on two hypotheses: (I) The primary component is a main-sequence star and the secondary fit's its Roche lobe; (2) The system is in the pre-main-sequence evolutionary phase. Key words: eclipsing binary - photometry - photometric elements