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Two Flare Stars and new CV discovered by MASTER

ATel #6069; P. Balanutsa, 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, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 14 Apr 2014; 20:00 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

Subjects: Optical, Cataclysmic Variable, Transient, Variables

Referred to by ATel #: 6104

MASTER OT J140957.49+290922.7 - flaring red dwarf

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 14h 09m 57.49s +29d 09m 22.7s on 2014-04-03.67682 UT. The OT unfiltered magnitude is 17.6m (limit 18.7m). There is no minor planet at this place. We have reference image without OT on 2014-04-03.64528 UT with unfiltered magnitude limit 18.6m. The object was not present on the first triplet of images taken 45 minutes before (on 2014-04-03.646 UT) and on the next set of images 45 minutes later (on 2014-04-03.708 UT) to the limiting magnitude 18.7.

The OT at quiescence is identical to the red star (g=23.44 r=21.91 i=19.45) = 2MASS J14095763+2909216 (J=16.12+/-0.10 H=15.57+/-0.14 K=15.34+/-0.15) = AllWISE J140957.52+290922.3 (W1=15.34+/-0.04 W2=15.17+/-0.04). There is nothing at this position in 1RXS, GALEX, GCVS and AAVSO VSX.

Based on the color, amplitude and rapid fading, MASTER OT J140957.49+290922.7 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/140957.49290922.7.png

MASTER OT J072448.87+533952.1 - flaring red dwarf

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 07h 24m 48.87s +53d 39m 52.1s on 2014-04-08.54936 UT. The OT unfiltered magnitude is 14.3m (limit 17.4m). The OT is seen in 16 images. We have reference image with OT at 16.9m on 2011-12-03.76594 UT (unfiltered magnitude limit 20.1m). The object was quickly fading: Apr. 08.548 UT, 14.12m; 08.549 UT, 14.33m; 08.551 UT, 14.82m. It has returned to quiescence at 17.1m on the second triplet of images obtained 1.1 hr later, on 2014-04-08.596 UT.

The OT at quiescence is identical to the red star USNO-B1.0 1436-0182430 (07 24 48.861 +53 39 52.58 pmRA=-20 pmDE=-44 B1=20.56 R1=17.52 B2=19.76 R2=17.78 I=15.47) = 2MASS J07244888+5339521 (J=13.69 H=13.13 K=12.85) = AllWISE J072448.87+533951.7 (W1=12.68 W2=12.45 W3=12.13). There is nothing at this position in 1RXS, GCVS and AAVSO VSX.

Based on the color, amplitude and rapid fading, MASTER OT J072448.87+533952.1 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/072448.87533952.1.png

MASTER OT J170025.50+573030.8 - new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 17h 00m 25.50s +57d 30m 30.8s on 2014-04-12.99605 UT. The OT unfiltered magnitude is 18.6m (limit 19.0m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2010-04-20.90135 UT with unfiltered magnitude limit 19.9m.

There is a faint blue star near this position on digitized Palomar plates. It is present in GSC 2.3.2 with the coordinates 17 00 25.69 +57 30 31.9 and blue magnitude jmag=22.47. Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J170025+573030-BRIR5x5.jpg (2x zoom). There is nothing at this position in 1RXS, USNO, 2MASS, GCVS and AAVSO VSX. This area of sky in Draco is not covered by SDSS.

Based on the blue color and outburst amplitude (~4m), MASTER OT J004527.52+503213.8 is a new cataclysmic variable (dwarf nova in outburst). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/170025.50573030.8.jpg

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net