[vsnet-alert 6084] V405 Vul outburst

[Taichi Kato <tkato>]

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

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