Recent observations of humps and superhumps and an estimation of outburst parameters of the AM CVn star CR Boo

We present our observational results of AM CVn star CR Boo in the UBVR bands. Our observational campaign includes data obtained over 5 nights with the National Astronomical Observatory Rozhen, Belogradchik, and the AS Vidojevica telescopes. During the whole time of our observations the brightness of the system varied between 13.95 – 17.23 in the B band. We report the appearance of humps during the period of quiescence and superhumps during the active state of the object, (where the latter are detected on two nights). We obtain the superhumps periodicity for two nights, P_sh≈ 24.76-24.92 min. The color during maximum brightness is estimated as - 0.107 < (B-V)_0 < 0.257 and the corresponding temperature is in the range as 7700 [K] < T(B-V)_0 < 11 700 [K]. We found that CR Boo varies from bluer to redder in the nights with outbursts activity. The star becomes bluer during the times of superhumps.