[vsnet-campaign-dn 2999] SW UMa: further data analysis, dramatic change in superhump properties

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

SW UMa: further data analysis, dramatic change in superhump properties

Dear Colleagues,

   We have further analyzed the data, nightly observed by the VSNET
collaborators.  Thanks to the excellent condition, the evolution of the
superhumps during the middle-to-late stage of a superoutburst has been
recorded in unprecedented detail.

   On November 3, the amplitude of the superhumps once reached a minimum.
During this period, the superhump profile became very complex.  A noteworthy
feature is the appearance of ~5 min clear QPOs (super-QPOs).  On Nov. 4
and Nov. 5, the superhumps grew again.  The profile showed nightly changes,
-- from doubly peaked to sharp triangular shape -- which even looks like
a "miniature WZ Sge".  On Nov. 6, the waveform became slightly unstable,
suggesting a rapid fading phase occuring in immediate future.  Short-term
variations (some of them may be QPOs) persisted during this stage.

   Please follow this object as intensively as possible, even if the object
suddenly fade.  A continuous watch for a possible rebrightening is also
very encouraged.

Regards,
Taichi Kato
VSNET Collaboration team

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