[vsnet-outburst 4019] V844 Her outburst!

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

V844 Her outburst!

  Hazel McGee reports that this short-period (Psh=0.05592 d) SU UMa-type
dwarf nova is undergoing an outburst.  The last confirmed outburst was
in 2001 August (superoutburst, not studied in detail because of the
co-occurrence of the WZ Sge outburst!), and a possible unconfirmed sighting
in 2002 February at 13.5.  The following description is still valid,
although the outburst intervals have become slightly more irregular
than given in the 2000 paper.  The object resembles SW UMa in its outburst
pattern, and further detailed observations are strongly encouraged.

Regards,
Taichi Kato
VSNET Collaboration team

[Excerpt from Kato and Uemura (2000) IBVS 4902]

   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.

  YYYYMMDD(UT)   mag  observer
  20020430.875  <150  (Pavol A. Dubovsky)
  20020430.978  <156  (Gary Poyner)
  20020501.988  <150  (Pavol A. Dubovsky)
  20020502.008  <150  (Gary Poyner)
  20020502.441  <141  (Michael Poxon)
  20020502.917  <141  (Eddy Muyllaert)
  20020502.944  <156  (Pavol A. Dubovsky)
  20020502.965  <156  (Gary Poyner)
  20020503.258  <141  (Mike Simonsen)
  20020503.899  <141  (Jose Ripero)
  20020503.911  <156  (Maciej Reszelski)
  20020504.215  <151  (Mike Simonsen)
  20020504.965  <141  (Hazel McGee)
  20020505.922  <150  (Pavol A. Dubovsky)
  20020505.960  <140  (Timo Kinnunen)
  20020506.971  <150  (Pavol A. Dubovsky)
  20020507.913  <135  (Eddy Muyllaert)
  20020507.947  <141  (Hazel McGee)
  20020507.950  <150  (Timo Kinnunen)
  20020507.972  <150  (Pavol A. Dubovsky)
  20020508.928  <150  (Pavol A. Dubovsky)
  20020509.953  <150  (Pavol A. Dubovsky)
  20020509.969  <150  (Timo Kinnunen)
  20020510.026  <156  (Maciej Reszelski)
  20020511.241  <150  (Mike Simonsen)
  20020511.953  <150  (Pavol A. Dubovsky)
  20020513.031  <150  (Pavol A. Dubovsky)
  20020513.917  <136  (Wolfgang Kriebel)
  20020513.946  <156  (Maciej Reszelski)
  20020514.007  <150  (Pavol A. Dubovsky)
  20020514.941  <141  (Eddy Muyllaert)
  20020515.304  <150  (Mike Simonsen)
  20020515.956  <150  (Gary Poyner)
  20020516.928  <136  (Hazel McGee)
  20020516.933  <156  (Maciej Reszelski)
  20020516.992  <150  (Pavol A. Dubovsky)
  20020517.919  <156  (Maciej Reszelski)
  20020518.931   125  (Hazel McGee)

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