[vsnet-alert 7626] GZ Cnc: unusual humps and oscillations continue!

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

GZ Cnc: unusual humps and oscillations continue!

Dear Colleagues,

   We have received the most recent GZ Cnc observations from Greb Bolt and
Arto Oksanen (comprising an almost continous coverage).  Although the data
show a further fading, the fading rate is slower than those of normal
outbursts of SU UMa stars.

   The most prominent feature on January 30 is the presence of large-amplitude
humps, but the dominant period is drastically different from the night
before.  The main period on January 30 is around 0.075 d, and whose profile
even looks like superhumps!  These modulations may be so-called negative
superhumps, but the period seems to be slighy too short.  As one could
easily imaging, we already have and expect to receive many, many data,
which have not been yet incoporated into this analysis.  With these complete
data, we can fill the gap and make a more decisive conclusion on the
nature of this long-period modulations.

   The short-period modulations (10-20m period) are still persistent,
although the amplitude has become slightly smaller.

   Anyway, the behavior of the present outburst of GZ Cnc does not seem
to fit any existing category of dwarf nova outbursts.  Please continue
keeping on your close eye on this unusual object!

Regards,
Taichi Kato

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