[vsnet-alert 15205] CSS 100615:215815+094709 very bright outburst!

[Denis Denisenko]

This outburst was already reported by Eddy Muyllaert in cvnet-outburst
message 5128. He has measured unfiltered magnitude 12.75: from the
image taken by Bradford Robotic Telescope on 2012 Dec 22.8535 UT.

MASTER-Amur telescope has also detected this star in outburst 14 hours
later on two unfiltered survey images (60-sec expousres). The
automatic photometry (with USNO-B1.0 red zero point) is as follows:

CSS 100615:215815+094709
  20121223.425  11.33CR  MASTER-Amur
  20121223.457  11.38CR  MASTER-Amur

USNO-B red magnitudes for this area of sky may be off. The CV at
quiescence has the following magnitudes:
USNO-B1.0 0997-0603766
R.A.=21 58 15.315 Dec.=+09 47 09.70 pmRA=10 pmDE=-46
B1=16.91 R1=15.89 B2=17.60 R2=15.98 I=16.99

However, SDSS quiescent magnitudes are fainter:
SDSS J215815.31+094709.0 u=17.59 g=17.48 r=17.61 i=17.55 z=17.15
http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237678858458497145

The star also has an UV counterpart GALEX J215815.2+094710
(FUV=17.88+/-0.05 NUV=17.76+/-0.04).
Yet the infrared colors are unusually high (J-K=0.90+/-0.12):
2MASS 21581531+0947095 J=15.898+/-0.065 H=15.181+/-0.087 K=14.904+/-0.110

Light curve from Catalina Sky Survey:
http://nesssi.cacr.caltech.edu/catalina/20100615/1006151091174130008p.html
Discovery outburst: 2010 June 15 (13.3), June 24 (13.6), July 04 (15.0).

Additional outburst was detected on the images by NEAT project taken
on 2003 Aug. 07.

During the 2010 outburst superhump period was measured to be 0.0776d.

Denis Denisenko