[vsnet-alert 11492] VX For: constant superhump period, WZ Sge-type similar to EG Cnc?

[Taichi Kato]

VX For: constant superhump period, WZ Sge-type similar to EG Cnc?

   We have received further observations from Arto Oksanen and Eric Southgate
(The Hermitage Observatory) and Berto Monard.  Rather surprisingly, the
superhump period has remained constant after the initial "period break".
The mean superhump period has been 0.06130(1) d.  This constancy of the
superhump period is very unusual for this short superhump period.
The possibilities would be either (1) we are observing the stage C
superhumps, rather than stage B, or (2) the object has an unusual small
Pdot as in extreme WZ Sge-type dwarf novae.
Either possibility would suggest that the true maximum was missed.
The ASAS-3 observations seem to strengthen this interpretation.

  YYYYMMDD(UT)   mag  observer
  20090831.3695 <14.50V  (ASAS (Pojmanski, G. 2002, Acta Astron. 52,397))
  20090910.3246 12.614V  (ASAS (Pojmanski, G. 2002, Acta Astron. 52,397))
  20090914.635   130  (Rod Stubbings)
  20090915.555   127  (Rod Stubbings)
  20090915.569   128  (Rod Stubbings)
  20090915.669   130  (Rod Stubbings)
  20090915.701  13.00V  (Higashi-Hiroshima Observatory (Hiroshima Univ.))
  20090918.497   128  (Rod Stubbings)
  20090918.599   130  (Rod Stubbings)

   If this object is indeed a WZ Sge-type dwarf nova, this object, with
a small Pdot, is expected to show repetitive rebrightenings
(cf. arXiv:0905.1757).  Continued observations are vital to test this
expectation.