Re-brightening and photometric modulation of the optical transient SSS130101:122222-311525

ATel #4744: Vitaly Neustroev (University of Oulu) and George Sjoberg (AAVSO):

We report a re-brightening and the consecutive detection of a photometric modulation of the recently discovered bright optical transient SSS130101:122222-311525 (Drake et al., ATel#4699).

This object has been in outburst since at least Dec 16, 2012 when it was found to be at V~11.8 (ATel#4700), some 7 mag brighter than it was previously. Subsequent photometry on Jan 1, 2013 showed the object still near maximum light at V = 12.3 +/- 0.1 (ATel#4699). However, the most recent reports indicated that SSS130101:122222-311525 had faded to magnitude 15.5 on Jan 4 and 16 on Jan 5 (vsnet-alert 15248).

Nevertheless, the data from our photometric monitoring indicate that after this decline a new increase in brightness has been observed during the last days. We performed time-resolved photometric observations of the object on Jan 10, 16 and 17 with the 0.35-m Celestron C14 robotic telescope, located at New Mexico Skies in Mayhill, New Mexico. We used an SBIG ST-10XME CCD camera with Johnson-Cousins BVRI Astrodon Photometric filters. On Jan 10, we obtained 10 images with an exposure time of 60 sec which gave an average magnitude of V=13.74+/-0.04. On Jan 16, we performed 2-hours of time-resolved observations with an exposure time of 30 sec. The average magnitude of these observations was V=12.48+/-0.03. On Jan 17, we obtained 2h 20min of multicolor BVRI photometry. Exposure times were 15 seconds for the VRI filters and 30 seconds for B. These observations gave the following magnitudes:

B=12.62+/-0.04, V=12.54+/-0.03, R=12.46+/-0.03, I=12.42+/-0.04

The observations from Jan 16 and 17 also revealed a photometric modulation with an amplitude of ~0.08 mag and a period of about 95 min or slightly longer. This period agrees with the estimates of Kuulkers et al. based on the spectroscopic observations (ATel#4716,#4704).

Kuulkers et al. proposed a WZ Sge-type dwarf nova classification for SSS130101:122222-311525. If this is correct then the object is expected to show a superhump signal during decline from superoutburst. We note, however, that even if the detected modulation is a superhump, the corresponding orbital period is still longer than WZ Sge stars usually have. This puts the WZ Sge classification of SSS130101:122222-311525 in doubt.

Photometry of SSS130101:122222-311525

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This entry was posted on Friday, January 18th, 2013 at 03:14 and is filed under Astronomy, Observations, Publications. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

One Response to “Re-brightening and photometric modulation of the optical transient SSS130101:122222-311525”

Dr. Vitaly Neustroev » Blog Archive » Monitoring of SSS130101:122222-311525 January 22nd, 2013 at 19:50

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