[vsnet-alert 10526] Possible SN from CBAT Unconfirmed Observations Page is CV!

[Korotkiy Stas]

Regarding Possible Supernova on CBAT Unconfirmed Observations Page

(psn 22 42 07.04 +29 22 28.4 16.5 R 8W 9N)

T. Kryachko and B. Satovskiy (Astrotel obs., KSU) and S. Korotkiy 
(Ka-Dar obs., Moscow) confirmed possible supernova at coordinates: 
R.A.=22h 42m 07.024s +/-0.03", DEC=+29d 22' 28.14" +/-0.04" (reduction 
with reference to UCAC-2) on three images in red filter with 300 sec 
exposure (limiting Red-filter mag 20.5) obtained on Sep. 12.747 UT with 
the Takahashi FRC-300 (D=300mm, F=2330mm) + CCD Apogee Alta U9000 at 
Kazan State University Astrotel observatory (Karachay-Cherkessia, 
Russia). We have measured red magnitude (reference star USNO A2.0 
1125-19454507, R=16.3) of the transient R=16.97; Sep. 12.976 UT, R=17.38 (red); Sep. 12.983 UT, B=16.72 (blue) (B-R=-0.66 - is UGWZ type CV?). 
 
CCD image of psn: http://www.astroalert.su/files/psn20080912.jpg

D. Denisenko (IKI, Moscow) reports that there is a faint object (Blue 
magnitude about 21.0) at the limit of sensitivity on two Blue Palomar 
plates taken 1954 Aug. 08 (POSS-I O) and 1992 Oct. 19 (POSS-II B) with 
the following coordinates (J2000.0):

22 42 07.08 +29 22 27.3

Blue Palomar plate: http://hea.iki.rssi.ru/~denis/224207+292228-DSS-B.jpg

The object implied by the discoverers as a possible host galaxy appears 
starlike on NEAT images. It is present in 2MASS catalogue as 2MASS 22420774+2922179 (J=16.838+/-0.155, H=16.056+/-0.184, K=15.701+/-0.227) 
which is consistent with it being an extragalactic source, probably a 
quasar (J-K>1.0). However, its relation to the optical transient 8"W 
and 9"N seems unlikely, given the OT proximity to the blue faint object 
on Palomar plates. Judging from amplitude of variability, it is likely 
a cataclysmic variable in outburst.

Sum of 18 NEAT images: http://hea.iki.rssi.ru/~denis/224207+292228-NEAT.jpg

There are no previous outbursts on the Palomar-NEAT images taken on 2001 
July 27, Aug. 09, 13, 18, Sep. 24; 2002 Sep. 27, 28, Oct. 10 and 14.