We report simultaneous multicolour observations in 5 bands ( UBVRI ) of the flickering variability of the cataclysmic variable AE Aqr .
Our aim is to estimate the parameters ( colours , temperature , size ) of the fireballs that produce the optical flares . The observed rise time of the optical flares is in the interval 220 - 440 sec .
We estimate the dereddened colours of the fireballs : ( U - B ) _ { 0 } in the range 0.8-1.4 , ( B - V ) _ { 0 } \sim 0.03-0.24 , ( V - I ) _ { 0 } \sim 0.26-0.78 .
We find for the fireballs a temperature in the range 10000 - 25000 K , mass ( 7-90 ) \times 10 ^ { 19 } g , size ( 3-7 ) \times 10 ^ { 9 } cm ( using a distance of d = 86 pc ) .
These values refer to the peak of the flares observed in UBVRI bands . The data are available upon request from the authors .