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Two OTs and Possible Supernova discovered by MASTER

ATel #5536; V. Yecheistov, P. Balanutsa, D. Denisenko, E. Gorbovskoy, V. Lipunov, M. Pruzhinskaya, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov (Moscow State University, SAI), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational 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 Pulkovo Observatory), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), P. Podvorotny, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 2 Nov 2013; 12:06 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Supernovae, Transient, Variables

Referred to by ATel #: 5585

MASTER OT J171648.24+775256.5 - flaring red dwarf

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 17h 16m 48.24s +77d 52m 56.5s on 2013-10-28.82497 UT. The OT unfiltered magnitude is 16.8m (limit 18.0m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-08-21.60105 UT with unfiltered magnitude limit 19.0m. The object was not visible on three images obtained 45 minutes earlier (Oct. 21.793-21.795 UT, m_lim=18.0). It has quickly faded within 3 minutes: Oct. 28.824, 16.2; 28.825, 16.8; 28.826, 17.5:.

The OT is identical to the red star SDSS J171648.21+775255.3 (u=25.70+/-0.82, g=21.96+/-0.08, r=20.35+/-0.04, i=18.33+/-0.01, z=17.29+/-0.02). It also has an infrared counterpart 2MASS 17164820+7752551 (J=15.66+/-0.07, H=15.09+/-0.09, K=14.89+/-0.16). There is nothing at this position in 1RXS, GCVS and AAVSO VSX. This area of sky in Ursa Minor is not covered by Catalina Sky Survey and NEAT.

Based on the red color and fast variability we conclude that MASTER OT J171648.24+775256.5 is a new variable of UV Ceti type (flaring red dwarf). Follow up observations are desirable. Discovery and reference images are available at: http://master.sai.msu.ru/static/OT/171648.24775256.5.png

MASTER OT J021315.37+533822.7 - new CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 02h 13m 15.37s +53d 38m 22.7s on 2013-10-31.69413 UT. The OT unfiltered magnitude is 17.2m (limit 18.7m). The OT is seen in 10 images. There is no minor planet at this place. We have reference image without OT on 2012-01-31.56698 UT with unfiltered magnitude limit 18.4m. The object has brightened to 16.8m by 2013-11-01.727 and 01.772 UT.

The OT is identical to the blue star USNO-B1.0 1436-0066814 (02 13 15.505 +53 38 23.29 pmRA=6 pmDE=6 B1=17.03 R1=16.73 B2=20.58) and USNO-A1.0 1425-03102216 (02 13 15.49 +53 38 22.8 R=16.3 B=16.6). The star was caught in outburst on the POSS-I blue and red plates but at quiescence on Quick-V and POSS-II plates. Comparison of 1st and 2nd epoch Palomar blue plates taken on 1954-10-03 and 1990-11-08 is posted at http://master.sai.msu.ru/static/OT/J021315+533822-POSS-B.jpg (5'x5' FOV). The object is also visible in ultraviolet as GALEX J021315.3+533822 (NUV=20.43+/-0.28). There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Perseus is not covered by SDSS, Catalina Sky Survey and NEAT.

Based on the blue color, UV counterpart and amplitude of variability we conclude that MASTER OT J021315.37+533822.7 is a new cataclysmic variable (dwarf nova in early stage of outburst). Follow up observations are required. Discovery and reference images are available at: http://master.sai.msu.ru/static/OT/021315.37+533822.7.jpg

MASTER OT J080659.02+460811.6 - possible Supernova

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 08h 06m 59.02s +46d 08m 11.6s on 2013-11-01.81105 UT. The OT unfiltered magnitude is 17.4m (limit 19.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-01-27.65652 UT with unfiltered magnitude limit 20.0m.

The OT is located 8.7" east and 10.4" south of the center of the galaxy PGC 22774. We have reported the object to CBAT TOCP as PSN J08065902+4608116. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/080659.02+460811.6.jpg

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net