[vsnet-alert 12493] Re: On the past standstills of WW Cet

Taichi Kato tkato at kusastro.kyoto-u.ac.jp
Mon Dec 13 15:03:50 JST 2010

Re: On the past standstills of WW Cet

> There is no obvious standstill in the data for either year. In 1991
> (left) the October outburst is clearly visible, but WW Ceti continues
> to vary between 12.0 and 14.0 afterwards. In 1992 (right), there is a
> slight gap in the regular outburst cycle, but nothing resembling a
> standstill.

   Although there is always a question how to define standstills
(Ringwald et al. apparently questioned this point), the difference
in interpretation may have somehow resulted from the said
problem in comparison stars (although I'm not sure what charts were used
at that epoch; Japanese observers probably used Huruhata chart,
photovisually calibrated one).

   According to the VSOLJ data, the object was recorded between 12.7-13.1
(disregarding some questionable "fainter than"s) between Nov. 6 and Dec. 13.
Typical quiescent magnitude on the same system was 13.5-14.5 (visual and pv).
The duration was at least 37 d (although not as long as the current 90-d one).
Most notable was that the presence of a standstill was (probably first)
communicated real-time, and was checked by different observers
(there was a document in Japanese confirming the suggested Z Cam-type
classification, and we have consistently used UGZ subtype in our
circulars, etc.)
The 1992 one was less obvious, but the object stayed brighter than its
normal quiescence.

More information about the vsnet-alert mailing list