A normal and superoutburst study of the eclipsing SU UMa star: DV Ursae Majoris

We report on time-resolved photometry carried out during the 1995 short out burst and the 1997 long outburst in the eclipsing dwarf nova DV UMa. The re vised orbital period is 0.0858526172 (67) d. We detected gigantic superhump s with an amplitude of similar to0.6 mag in the mid-phase of the 1997 outbu rst, revealing the SU UMa nature of DV UMa. The superhump period is 0.0887 (4) d. The superhumps became less clear during the late phase of the supero utburst, and we found two possible periods of 0.0885 (15) and 0.0764 (15). During both outbursts, the eclipse was wide and shallow near the maximum, a nd then became narrower and deeper, which is qualitatively well explained b y the current disc instability theory.