V405 Vul outburst As reported in vsnet-outburst 2520 by J. Pietz, the possible SU UMa-type dwarf nova V405 Vul is in outburst. > V405 Vul 2001-07-19.947 15.1 > > Regards, > Jochen Pietz The object is known to show variations resembling superhumps, but they have unstable periods. The other similar example is V344 Ori. These objects may represent a new class of dwarf novae, which have intermediate properties between SU UMa-type dwarf novae and SS Cyg-type dwarf novae. Observations during the present outburst is strongly encouraged. [vsnet-alert 5591, Tonny Vamunster] in response to the V344 Ori observation by the VSNET Collaboration team: > This kind of 1-hour scale, large amplitude modulations and irregularities, > and the corresponding ~0.12d periodicity are indeed not very frequently > observed in erupting dwarf novae, as far as I know and can deduce from my > CCD observations over the past 5 years. There's one very similar case > however, call it a 'twin' of V344 Ori, that comes to my mind, and that's > V405 Vul (S 10943). During the August 2000 outburst of V405 Vul, I followed > this object very intensively through CCD photometry, together with some > colleagues from other CBA stations (Bob Fried, Sergey Shugarov) for over 2 > weeks. We got dense coverage and Sergey and I have been making various > attempts to analyse the periodicities in this system, finding also values > around 0.12d - 0.14d. However, we never got secure, stable values over the > entire observing period. > > I think it would be worthwhile to give some priority to both objects in > terms of next outburst coverage. Moreover, they are an ideal 'couple', as > one is primarily a Summer target and the other a Winter target. Regards, Taichi Kato VSNET Collaboration team