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Flare Star, CV and Possible Supernova detected by MASTER

ATel #5676; P. Balanutsa, V. Shumkov, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, A. Rufanov, V. Vladimirov, V. Yecheistov (Moscow State University, SAI), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of Pulkovo Observatory), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (Irkutsk State University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), P. Podvorotny, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 20 Dec 2013; 13:49 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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

MASTER OT J223942.63+304027.1 - flaring red dwarf

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 22h 39m 42.63s +30d 40m 27.1s on 2013-12-17.45272 UT. The OT unfiltered magnitude is 16.0m (limit 17.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-08-09.73763 UT with unfiltered m_lim=19.2. The object was not visible on 10:48:46 UT unfiltered image (60-sec exposure, m_lim=17.5). It was first detected on 10:50:20 UT at 15.3m, faded to 16.0m on 10:51:55, ~17m on 10:53:28 and below 17.5m on 10:55:02.

The OT at quiescence is identical to the red star SDSS J223942.61+304028.3 (g=22.97 r=21.04 i=18.50 z=16.98) = 2MASS 22394253+3040284 (J=14.89 H=14.14 K=13.76). There is nothing at this position in 1RXS, GCVS and AAVSO VSX. No previous flares were detected by CRTS.

Based on the color, amplitude and short rise time MASTER OT J223942.63+304027.1 is the new variable of UV Ceti type. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/223942.63304027.1.png

MASTER OT J170515.37+724402.5 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 17h 05m 15.37s +72d 44m 02.5s on 2013-12-18.65655 UT. The OT unfiltered magnitude is 16.3m (limit 17.3m). The OT is seen in 7 images. We have reference image without OT on 2012-08-21.59546 UT with unfiltered m_lim=19.5.

The OT at quiescence is identical to the blue star USNO-A2.0 1575-03747443 (17 05 15.43 +72 44 03.3 R=19.4 B=19.0) = USNO-B1.0 1627-0127716 (17 05 15.345 +72 44 03.50 pmRA=0 pmDE=0 B1=19.44 B2=19.48 R1=19.11 R2=19.24 I=N/A) = SDSS J170515.34+724403.5 (u=17.65 g=17.30 r=17.49 i=17.66 z=17.81). There is also an UV counterpart GALEX J170515.4+724402 (FUV=20.85+/-0.11 NUV=20.10+/-0.06). Finally, there is a faint X-ray source 1RXH J170515.6+724404 in ROSAT catalog of HRI pointed observations with the flux 0.0020 cnts/s.

The object is showing significant variability between the Palomar plates. It is listed in GSC 2.3.2 with the blue magnitude 16.53. It was faint on 1987-06-01, 1992-04-08 and 1992-04-09 POSS-II blue plates and bright on 1992-07-27 plate. Comparison of 1992 Apr. 09 and July 27 plates is uploaded to http://master.sai.msu.ru/static/OT/J170515+724402-POSS-B.jpg (5'x5' FOV).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Draco is not covered by CRTS. The object is listed in Simbad as possible quasar. Atlas of Radio/X-ray associations (Flesch, 2010) gives a 97% probability of the object being a QSO, 1% galaxy and 1% star. Girven et al., 2011 (MNRAS 417, 1210) list the object as a white dwarf with T_eff=12000 K and log(g)=8.25 cm/s2.

Based on the blue color and amplitude of variability (~3m), MASTER OT J170515.37+724402.5 is most likely a cataclysmic variable of AM Her type (polar) or a dwarf nova. Spectral and photometric observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/170515.37724402.5.png

MASTER OT J140412.97-093816.8 - possible Supernova

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 14h 04m 12.97s -09d 38m 16.8s on 2013-12-20.11819 UT. The OT unfiltered magnitude is 16.5m (limit 17.9m). The OT is seen in 3 images. We have reference image without OT on 2010-04-19.90778 UT with unfiltered m_lim=20.3.

The OT is located 10" east and 13" north of galaxy IC 4363 = 2MASX J14041231-0938297 (J=12.77 H=11.96 K=11.72) = SDSS J140412.27-093830.3 (g=15.63 r=14.76 i=14.30). Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/140412.97-093816.8.jpg

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net