[vsnet-alert 1197] CVC 153 (clear superhumps in USNO 1425.09823278)

[Tonny Vanmunster <tvanmuns@innet.be>]

BELGIAN ASTRONOMICAL SOCIETY V.V.S. -  Working Group Variable Stars
Cataclysmic Variables Circular No.153            1997, September 11
Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM
     Internet: tvanmuns@innet.be                  TEL. 32-11-831504
     CVC Web Page : http://vsnet.astro.columbia.edu/~cba/cvc
===================================================================

USNO 1425.09823278 [UGSU, 13.3R - 19.9R]
========================================

Unfiltered CCD observations of this object, obtained over a 7.8h 
run on Sep 10/11, 1997 (during the rebrightening reported in our
previous CVC) at CBA Belgium Observatory, show the existence of
superhumps with a mean semi-amplitude of 0.05 mag. An analysis
using the PDM method shows a distinct signal at 0.0561 +/- 0.0004 d,
which clearly is the superhump period. A steady linear trend of
decline (approx. 0.3 mag over 8 hours) was removed from the 
observations.

Given the dominance of this signal, and taking into account the
fact that the period is in very good agreement with values obtained
during earlier runs [CVC 149 & CVC 151], we feel very confident
we finally have revealed the SU UMa-type nature of this newly
discovered variable. 

Follow-up observations are of course still highly encouraged. A
quick inspection of tonight's CCD data shows that the object has
become faint again (the linear trend of decline, reported above,
presumably has not been interrupted).


Tonny Vanmunster

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