Flare Star and new Cataclysmic Variable detected by MASTER

ATel #6049; D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, P. Balanutsa, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, A. Rufanov, V. Vladimirov, V. Yecheistov (Moscow State University, SAI), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of Pulkovo Observatory), 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 (Irkutsk State 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 7 Apr 2014; 13:21 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J124017.72-040542.9 - flare star of UV Ceti type

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 12h 40m 17.72s -04d 05m 42.9s on 2014-04-03.81899 UT. The OT unfiltered magnitude is 17.3m (limit 19.3m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2014-02-01.01249 UT with unfiltered magnitude limit 19.4m. The object was first detected on the 60-sec exposure starting at 2014-04-03 19:37:53 UT with unfiltered magnitude 16.9 (m_lim=19.3) fading to 17.3m on the next two images on 19:39:21 and 19:40:53 UT. It is not present on the second triplet of images taken 1.1 hr later (at 20:44:50 UT, or on 2014-04-03.864 UT) to the limiting magnitude 18.7.

The OT at quiescence is identical to the red star SDSS J124017.67-040542.6 (g=21.78 r=20.39 i=18.87) = 2MASS J12401764-0405427 (J=16.50+/-0.12 H=15.94+/-0.14) = AllWISE J124017.67-040542.8 (W1=15.79+/-0.05 W2=15.79+/-0.16). There is nothing at this position in 1RXS, GALEX, GCVS and AAVSO VSX. There was a possible previous flare to 17.1m detected by Catalina Sky Survey on 2009-06-14.163, see the light curve of CSS J124017.7-040543.

Based on the color, amplitude and rapid fading, MASTER OT J124017.72-040542.9 is a flaring red dwarf. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/124017.72-040542.9.png

MASTER OT J182205.85+270849.7 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 18h 22m 05.85s +27d 08m 49.7s on 2014-04-05.72185 UT. The OT unfiltered magnitude is 16.2m (limit 17.8m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2012-08-21.62466 UT with unfiltered magnitude limit 18.8m. The object was observed in a brighter outburst to 15.1m on a single MASTER-Amur image on 2013-01-27.916 UT but was not detected as a transient then.

The OT at quiescence is identical to the blue star USNO-B1.0 1171-0355226 (18 22 05.838 +27 08 50.27 pmRA=-2 pmDE=8 B1=20.04 R1=N/A B2=20.33 R2=N/A I=18.93). Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J182205+270849-BRIR.jpg (10'x10' FOV).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Hercules is not covered by SDSS and GALEX. Object was at minimum light on 12 DSS plates and on 11 NEAT images on 4 different nights from 1997-09-02 to 1998-08-19. There was an outburst to 15.9m in Mount Lemmon Survey data on 2006-05-04.394 UT, see MLS J182205.8+270849.

Based on the blue color and amplitude of variability, MASTER OT J182205.85+270849.7 is a cataclysmic variable (dwarf nova in outburst). Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/182205.85270849.7.png

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