V485 Centauri: the Shortest Period SU UMa Star ∗

We report CCD observations of the dwarf nova V485 Cen during its 1997 su-peroutburst. The long lasting outburst with characteristic slope, brightness dip and presence of clear superhumps give evidence that V485 Cen belongs to the group of SU UMa-type variables. The superhump period is equal to 0. d 042156 ± 0. d 000004 (60. m 7). Thus, V485 Cen has the shortest known period among SU UMa-type stars, with a period as much as 25% shorter than previously known objects. The analysis of times of superhump maxima gives clear evidence for the increase of superhump period with ˙ P sh = 28.3 × 10 −5. This fact confirms the hypothesis that the shortest periods SU UMa variables contrary to other stars of this type have positive values of ˙ P sh .