REPETITIVE REBRIGHTENING IN THE DWARF NOVA EG CANCRI

A dwarf nova of the WZ Sge-type, EG Cnc, which had a superoutburst in 1996 December after 19 years of dormancy exhibited, after the end of t he main outburst, six repetitive short outbursts with a mean interval of about 7 days. We propose that this rebrightening phenomenon of EG C nc may have been produced by a thermal disk instability, which could i n turn have been caused by a temporal increase in the viscosity at a c old state. We suggest that an increase in viscosity in quiescence coul d be produced by a highly turbulent state in the disk due to an after- effect of the main outburst. Our numerical simulations based on this m odel can reproduce very well the observed light curve of EG Cnc. We di scuss a possible cause why the WZ Sge-type dwarf novae show post-outbu rst rebrightening.