Detection of the eclipsing dwarf nova nature of SDSS J122740.83+513925.0

On 2007, June 4th, 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 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. My observations cover 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.

Lightcurve of SDSS J122740.83+513925.0 on 2007, Jun 04/05,
showing the presence of 2 eclipses, superimposed on another periodic modulation.

The orbital period of the system has been determined using Peranso's Kwee-van Woerden
and Polynomial Fit methods (the latter one is depicted above).

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.

Thanks to Patrick Schmeer and Arne Henden. 





Copyright © 2007 - Tonny Vanmunster.