New Bright CV detected by MASTER

ATel #5111; D. Denisenko, V. Lipunov, E. Gorbovskoy, P. Balanutsa, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Yecheistov (Moscow State University, SAI), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov, A. Punanova (Ural Federal University), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova (Irkutsk State University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk solar station of the Pulkovo observatory RAS), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), P. Podvorotny, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 6 Jun 2013; 18:31 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J212624.16+253827.2 - new bright CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 21h 26m 24.16s +25d 38m 27.2s on 2013-06-06.66618 UT. The OT unfiltered magnitude is 14.2m (limit 16.5m). The OT is seen in 13 images. There is no minor planet at this place. We have reference image without OT on 2013-03-31.81715 UT with unfiltered magnitude limit 17.5m.

The OT is identical to the blue star USNO-A2.0 1125-18372982 (21 26 24.20 +25 38 28.4 B=18.5 R=18.3) and USNO-B1.0 1156-0515545 (21 26 24.151 +25 38 27.23 pmRA=-14 pmDE=-24 B1=19.27 R1=18.73 B2=18.75 R2=19.54 I=18.18). SDSS DR9 has an object in outburst with the following entry in Photometric Catalog: SDSS J212624.13+253826.9 u=15.02 g=14.51 r=14.67 i=14.81 z=14.93 (ObsDate=2009.8783). SDSS finder chart can be found here. There is an UV counterpart GALEX J212624.2+253827 (NUV=20.81+/-0.26). This area of sky in Vulpecula is not covered by Catalina Sky Survey. No previous outbursts were detected on 9 digitized Palomar plates. There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX.

The object was observed by MASTER in several outbursts before, but was not detected as a transient. Outburst dates (mid-exposures) and magnitudes (unfiltered with the red zero point) are listed in table below.

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Obs. date, UT    Mag   Observatory 
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2012-06-22.734  14.17  MASTER-Amur 
2012-06-24.834  14.82  MASTER-Kislovodsk 
2012-06-24.882  14.86  MASTER-Kislovodsk 
2012-12-21.466  13.73  MASTER-Amur 
2012-12-23.405  13.93  MASTER-Amur 
2013-03-29.836  14.85  MASTER-Amur 
2013-06-06.634  14.16  MASTER-Amur 
2013-06-06.666  14.06  MASTER-Amur 
2013-06-06.667  14.19  MASTER-Amur 
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Based on the blue color, amplitude of variability (~5m) and multiple previous outbursts we conclude that MASTER OT J212624.16+253827.2 is a new cataclysmic variable (dwarf nova), likely of UGSU (SU UMa) subtype. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/212624.16253827.2.png

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