[vsnet-alert 5122] V844 Her outburst, as predicted by Watanabe-san!

[Taichi Kato <tkato>]

V844 Her outburst, as predicted by Watanabe-san!

  Watanabe outburst has come!

[vsmet-future 12] on July 1:
> V844 Her outburst prediction by Watanabe
> 
>    Tsutomu Watanabe predicts that the next (super?)outburst of V844 Her
> will occur within two weeks.

  YYYYMMDD(UT)   mag  observer
  20000708.930  <150  (J. Ripero)
  20000709.410  <150  (G. Hanson)
  20000709.906  <147  (M. Reszelski)
  20000710.257  <141  (M. Simonsen)
  20000710.923  <142  (M. Reszelski)
  20000710.960  <153  (G. Poyner)
  20000711.219  <141  (M. Simonsen)
  20000711.933  <141  (E. Muyllaert)
  20000711.949  <150  (G. Poyner)
  20000712.174  <141  (M. Simonsen)
  20000712.194  <150  (G. Hanson)
  20000713.917  <141  (M. Reszelski)
  20000714.924  <136  (H. McGee)
  20000714.962  <150  (G. Poyner)
  20000715.214  <141  (M. Simonsen)
  20000715.959  <141  (C. P. Jones)
  20000717.243   122  (R. J. Modic)

   The object is a short-period SU UMa-type system with a long outburst
interval.

   The importance of the object is stressed in our article in IBVS 4902
as cited below:

>    Aside from V485 Cen, almost all of SU UMa-type dwarf novae with the
> shortest superhump (orbital) periods belong either to what is called
> WZ Sge-type dwarf novae (Bailey 1979; Downes, Margon 1981; O'Donoghue
> et al. 1991) and ER UMa-type dwarf novae (for a review, see Kato et al.
> 1999).  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.  From available photometric materials
> (Antipin (1996) and observations to VSNET), long and bright outbursts
> (presumably superoutbursts) are separated by 220--290 d, without yet
> detectable normal outbursts.  Such a low frequency of normal outbursts
> resembles that of SW UMa, another SU UMa-type dwarf nova with a short
> orbital period, but the relatively regular occurrence of superoutbursts
> in V844 Her makes a slight difference.  It may be that V844 Her occupies
> a previously unknown extension of WZ Sge-type dwarf novae toward
> the short recurrence period.

   No outburst has been detected since the 1999 superoutburst.  This star
apparently has a "clock" without evident normal outbursts.  The present
outburst indeed warrants further time-resolved photometry, and is placed
as one of most important targets of the VSNET Collaboration team!

Regards,
Taichi Kato
VSNET Collaboration team

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