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Three Optical Transients discovered by MASTER

ATel #6141; P. Balanutsa, S. Shurpakov, V. Shumkov, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov, V. Yecheistov (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 (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 (MASTER team member), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 15 May 2014; 13:45 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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

MASTER OT J190812.83+572431.9 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 19h 08m 12.83s +57d 24m 31.9s on 2014-05-09.71591 UT. The OT unfiltered magnitude is 16.1m (limit 18.3m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-06-24.62045 UT with unfiltered magnitude limit 19.0m.

The OT at quiescence is identical to the blue star USNO-A2.0 1425-09492979 (19 08 12.78 +57 24 32.6 R=18.4 B=17.9) = USNO-B1.0 1474-0350118 (19 08 12.855 +57 24 32.45 pmRA=16 pmDE=0 B1=17.70 R1=18.17 B2=21.31 R2=N/A I=N/A). Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J190812+572431-BRIR5x5.jpg (2x zoom). The star was bright on 1952-07-27 blue and red POSS-I plates and faint on other Palomar images. Comparison of 1952-07-27 and 1989-07-25 blue plates is shown at http://master.sai.msu.ru/static/OT/J190812+572431-POSS-B.jpg (with star at the edge of FOV in July 1952).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Draco is not covered by SDSS and CRTS.

Based on the blue color and outburst amplitude (~5m), MASTER OT J190812.83+572431.9 is most likely a dwarf nova of SU UMa (UGSU) type in superoutburst. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/190812.83572431.9.png

MASTER OT J193657.39+445236.4 - flaring red dwarf in Kepler field

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 19h 36m 57.39s +44d 52m 36.4s on 2014-05-09.80723 UT. The OT unfiltered magnitude is 16.1m (limit 17.9m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-07-26.66203 UT with unfiltered magnitude limit 19.2m. The object was first detected at 15.7m on 19:19:42 UT and has faded by 0.4m in 5.3 minutes, by 19:25:01 UT.

The OT at quiescence is identical to the red star USNO-B1.0 1348-0341057 (19 36 57.352 +44 52 36.02 B2=N/A R2=19.29 I=17.47) = 2MASS J19365734+4452359 (J=15.48+/-0.05 H=14.89+/-0.06 K=14.53+/-0.09) = AllWISE J193657.34+445235.8 (W1=14.49 W2=14.32). There is nothing at this position in 1RXS, GALEX, GCVS and AAVSO VSX. This area of sky in Cygnus is not covered by SDSS. The star was included in Kepler input catalog as KIC 8695503. It is also listed in Extended Kepler-INT Survey catalog as KIS J193657.36+445235.9 (g=21.09 r=19.67 i=17.50).

Based on the color, amplitude and rapid fading MASTER OT J193657.39+445236.4 is a new variable of UV Ceti type (flaring red dwarf). Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/193657.39445236.4.png

MASTER OT J180958.28+192302.8 - possible CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 18h 09m 58.28s +19d 23m 02.8s on 2014-05-10.95576 UT. The OT unfiltered magnitude is 18.0m (limit 19.0m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-04-29.92875 UT with unfiltered magnitude limit 19.3m.

There is nothing at this position in any catalogs. This area of sky in Hercules is not covered by SDSS and CRTS. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J180958+192302-BRIR5x5.jpg (2x zoom).

MASTER OT J190812.83+572431.9 is likely a dwarf nova in outburst. Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/180958.28192302.8.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net