The contact eclipsing binary system XX Leonis ( p = 0.97 days , Sp A9 ) has been analysed using the PHOEBE programme , based on the Wilson-Devinney code .
The BVRI light curves were obtained during spring 2006 using the 20-cm telescope and ST-7 CCD detector .
The effective temperature of the primary component determined from the photometric analysis is T = ( 7342 \pm 14 ) K , the inclination of the orbit is i = ( 84.83 \pm 0.29 ) ^ { \circ } and the photometric mass ratio q = ( 0.40 \pm 0.01 ) .
Also the third body hypothesis was suggested , based on the period analysis using 57 minimum times and resulting the period of the third body p _ { 3 } = ( 59.66 \pm 0.05 ) yr , amplitude A = ( 0.036 \pm 0.028 ) day and zero eccentricity which gives the minimum mass M _ { 3 ,min } = ( 0.91 \pm 0.01 ) M _ { \odot } .