[Aavso-photometry] Detection of the eclipsing dwarf nova nature of SDSS J122740.83+513925.0

[Patrick Schmeer]

Dear observers,
 
Are there any updates on this dwarf nova? If SDSS J122740.83+513925.0
is still at mag 14-15 then it must be undergoing a superoutburst.
Btw, my revised estimate for June 4.106 UT is mag 14.3 (unfiltered).
 
Clear skies,
Patrick

--- Tonny Vanmunster <Tonny.Vanmunster at cbabelgium.com> wrote:

> Dear colleagues,
> 
> Yesterday evening I was informed by Patrick Schmeer about his detection of
> an outburst of SDSS J122740.83+513925.0 on June 4.106 UT at unfiltered mag
> 15. This object was discovered in the course of the SLOAN Digital Sky Survey
> and is reviewed in "Cataclysmic Variables from Sloan Digital Sky Survey. V.
> The Fifth Year (2004), Szkody et al." Based on a communication today with
> Arne Henden, one of the co-authors of this paper, SDSS J122740.83+513925.0
> is known as a CV, and is probably a high-inclination dwarf nova with a low
> orbital period.
> 
> Following Patrick's announcement, I started time-series CCD observations of
> SDSS J122740.83+513925.0 on June 4/5, 2007 at CBA Belgium Observatory, using
> one of the observatory's 0.35-m f/6.3 telescopes. I have just concluded an
> analysis of my CCD observations, covering a time span of 3.0 hours. They
> clearly show the presence of two eclipses, superimposed on another periodic
> modulation, hence classifying SDSS J122740.83+513925.0 as an eclipsing dwarf
> nova. Using Peranso, I find an orbital period of 0.0624 +/- 0.0001 d or 90
> min (extremum determination based on the Kwee-van Woerden method and on a
> Polynomial fit). The eclipses have a depth of 0.5 mag.
> 
> SDSS J122740.83+513925.0 appears to be a very interesting system, so I
> encourage follow-up photometry, to further determine the characteristics of
> this system.
> 
> I have posted my lightcurve on my website at www.cbabelgium.com, including a
> graph showing the orbital period analysis.
> 
> Thanks to Patrick Schmeer and Arne Henden.
> 
> Best regards,
> Tonny Vanmunster


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