Estimates of the radius of the accretion disk of the dwarf nova Pegasi 2010

The variations in the radius of the accretion disk of the WZ Sge dwarf nova OT J213806.6+261957 are estimated. The calculations are based on photometric observations of the object during a superoutburst that began on May 6, 2010. Shortly after the maximum, superhumps typical of WZ Sge stars appeared in the light curve of OT J2138. Photometric observations of the object between May 15 and December 2, 2010, reveal a variability in the period of the superhumps, so that it is possible to track the changes in the radius of the accretion disk during the superoutburst in terms of a model of tidal instability in the accretion disks of dwarf novae. It is shown that the radius of the accretion disk can exceed both the radius of the 3:1 resonance and the radius of the tidal effect from the secondary component.