ИСТИНА

Dwarf novae belong to the class of cataclysmic variables and represent the close binary systems on the late evolutionary stages. They consist of a white dwarf and a red dwarf which fills its Roche lobe and transfers mass to the white dwarf. The gas stream flows from the secondary to the primary white dwarf forming an accretion disk around it. Dwarf novae undergo outburst in semi-periodic intervals of time, when the brightness increases of 3 to 5 magnitude. SU UMa exhibit the special phenomenon, so-called «superhumps», on the light curve during superoutbursts (outbursts of larger amplitude and longer than normal ones). Superhumps represent an increase of the system brightness on the small part of the orbital light curve which repeated with the period a few percents longer than the orbital one. The amplitude of superhumps is around 0.1-0.3 mag. The orbital periods of these novae are about 80-180 min. The purpose of our study was an analysis of time-resolved photometry of program stars during superoutbursts which have been occurred in these systems during the last years. Our observations were carried out with CCD device on 50 cm and 60 cm telescopes of Sternberg Astronomical Institute Observatory in Crimea, mostly in R band. Superhumps were detected in the light curves of all systems. The amplitudes and periods of detected modulations were estimated. Evolution of superhumps was followed up and classification specified for all novae.