THE LIGHT-CURVE OF V1765 CYGNI - A CLOSE BINARY-SYSTEM WITH A SUPERGIANT COMPONENT

Using new and published UBV photometric obervations we constructed mea n light curves for the B0.5 Ib + BO-1V close binary system V1765 Cyg. The depths of the eclipses in U, B and V are 0(m).21, 0(m).15 and 0(m) .15 for primary minimum and 0(m).21, 0(m).15 and 0(m).13 for secondary minimum. There is significant scatter about the mean light curves; by autocorrelation analysis we find that it has a characteristic time sc ale of 1.5 or 3.0-3.5 days. There may be a small, slow brightening of the system outside of eclipse amounting to 0(m).02 in V over a decade.