Superoutburst of 206 SU UMa-type dwarf novae

Although there are now more than 1180 SU UMa-type dwarf novae catalogued, our knowledge on their superoutburst cycle length C_so_ has hitherto been limited to about 6 per cent of the entire sample of known SU UMa stars. Using public data bases we have determined new C_so_ values for a total of 206 additional SU UMa stars in the range 17d<C_so_<4590d (including some ER UMa and WZ Sge-type representants) within total time intervals between 2 and 57yr, and with an estimated uncertainty of +/-11 per cent.

This way, we are increasing our present knowledge of C_so_ values by a factor of ~3.8. Their distribution is characterized by a broad maximum around C_so_~270d, and slowly decreasing numbers up to C_so_~800d. The domain C_so_>450d was unexplored until now; we add here 106 cases (~51 per cent of our total sample) in this range of long cycles, implying a better statistical basis for future studies of their distribution.