Blue Flaring Object with Fast Variability discovered by MASTER

ATel #5872; V. Yecheistov, P. Balanutsa, D. Denisenko, V. Lipunov, N. Tiurina, E. Gorbovskoy, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, A. Rufanov, V. Vladimirov (Moscow State University, SAI), 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. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), 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 10 Feb 2014; 18:16 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J174045.80+115828.5 - new highly variable object in Ophiuchus

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 17h 40m 45.80s +11d 58m 28.5s on 2014-02-09.06939 UT. The OT unfiltered magnitude is 18.0m (limit 19.2m). The OT is seen in 4 images. There is no minor planet at this place. We have reference image without OT on 2012-06-14.93800 UT with unfiltered magnitude limit 19.7m. The object has faded below the detection limit (19.0m) on the images obtained an hour later, on 2014-02-09.115 UT.

The OT at quiescence is identical to the blue star USNO-B1.0 1019-0338114 (17 40 45.735 +11 58 28.80 B1=N/A R1=N/A B2=19.44 R2=18.82 I=N/A). Color-combined BRIR finder chart is uploaded to http://master.sai.msu.ru/static/OT/J174045+115828-BRIR5x5.jpg (2x zoom) and the near-infrared 2MASS JHK image - to http://master.sai.msu.ru/static/OT/J174045+115828-JHK5x5.jpg (same scale).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Ophiuchus is not covered by SDSS and GALEX. Galactic latitude is 21 deg. No previous flares were detected by Catalina Sky Survey. The object is showing the large variability on Palomar blue and red plates. Comparison of POSS-I and POSS-II blue plates is posted at http://master.sai.msu.ru/static/OT/J174045+115828-POSS-B.jpg (faint on 1956-03-15 and 1990-06-22, bright on 1990-07-20).

This area of sky was observed by NEAT project with 47 images on 16 different nights from 1998 July 19 to 2005 Aug. 30. The object has shown large variability on 2002 July 07 brightening by 1.5m within 1 hour (July 07.209 UT, 19.2; 07.230, 18.5; 07.251, 17.7) and on 2002 July 17 fading by 1.2m in 30 minutes (July 17.205 UT, 17.9; 17.226, 19.1). Animation of three 2002-07-07 NEAT images is uploaded to http://master.sai.msu.ru/static/OT/J174045+115828-NEAT2002-anim.gif

MASTER OT J174045.80+115828.5 is likely a binary system with a hot compact object undergoing short outbursts. Optical spectroscopy is required to determine the nature of this unusual object. Observations in X-rays are also encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/174045.80115828.5.jpg

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