[vsnet-alert 7279] V589 Her : superoutburst is over - new superhump period value ?

["Tonny Vanmunster" <Tonny.Vanmunster@advalvas.be>]

Dear colleagues,

I had another clear observing night on April 07/08, 2002, during which I
could successfully follow V589 Her (unfiltered CCD photometry at CBA Belgium
Observatory). The object again had faded compared to the previous night
(average unfiltered mag : 15.6C), and I had to use substantially longer
exposure times to generate sufficient 'counts'. 

The resulting light curve (see www.lunarpages.com/cbabelgium) still shows
the existense of 3 superhumps, although less qualified than on the previous
two nights. When combining this data set with my ohter available V589 Her
data (a total of 562 observations), I obtain a superhump period of 0.0864
+/- 0.0005 d, using the PDM technique. Important to note is that the period
diagram also shows a second possible period (of identical strength) at
0.0950 +/- 0.0005 d. This would turn V589 Her into a long-period UGSU dwarf
nova (inside period gap).

I'm expecting some further data sets from other CBA stations, and that
definitely will help to differentiate amongst both periods.

Sky conditions were very favourable also on Apr 08/09, but the object had
faded too much for my equipment to conduct time series photometry. It was at
about (unfiltered) mag 16.2 on 2002, Apr 08.93 UT.

Kind regards,
Tonny Vanmunster
CBA Belgium Observatory
www.lunarpages.com/cbabelgium

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