ИСТИНА

ER UMa is a well known SU UMa-type dwarf nova with a number of outstanding properties. It is the prototype of a small group of dwarf novae with a high frequency of superoutbursts and a short orbital period; once the phase reversal of “positive” superhumps during the very early stage of the superoutburst was detected; the “negative” superhumps during the superoutburst were discovered for the first time. Here we present the result of multicolor BVRcIc investigation of ER UMa carried out at the Crimean astrophysical observatory in 2020. Еvidence of co-existence of the “positive” and “negative” superhump in a quiet state and normal outbursts was found in ER UMa for the first time. The co-existence of both types of superhump suggests that the accretion disk in this system was eccentric and tilted at the same time