V844 Her: unique short orbital period SU UMa star Recent reports [1,2] on V844 Her (=Var43 Her) confirm the star as being an SU UMa star having one of the shortest superhump periods. A table of short Psh SU UMa stars (taken from [3]; stars with (*) are newly added here): Psh Porb --------------------------------------------------------- V485 Cen 0.0421 0.041 (*) DI UMa 0.0555 V844 Her 0.056 +/- 0.001 (*) LL And 0.05700 WZ Sge 0.05714 0.05669 AL Com 0.0572 0.05666 SW UMa 0.0583 0.05681 HV Vir 0.05865 0.05799 WX Cet 0.05936 0.0582 RZ LMi 0.05946 T Leo 0.0602 0.05882 EG Cnc 0.06036 0.05821 Aside from V485 Cen, all of these short Psh SU UMa stars are either what is called WZ Sge-type dwarf novae and ER UMa-type (or RZ LMi-type) dwarf novae. The former category contains WZ Sge, AL Com, HV Vir, EG Cnc, and related members LL And, SW UMa, WX Cet and T Leo. The latter group contains DI UMa and RZ LMi. Which group will V844 Her belong to, or comprise by itself a unique class? From available photometric materials ([4] and reports to VSNET), bright (super) outbursts are separated by 220-230 days, without detectable normal outbursts (despite the brightness of the object) so far. Will it mean V844 Her is a WZ Sge-type dwarf nova with a supercycle length of 220-230 (!) days? Regards, Taichi Kato (please continue the discussion in vsnet-chat if necessary) References: [1] T. Vanmunster, CVC 141, or http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-alert/msg00935.html [2] L. T. Jensen [vsnet-obs 5854] http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-obs/msg05854.html [3] D. Nogami, S. Masuda, T. Kato 1997, PASP submitted [4] S. V. Antipin 1996, IBVS 4360