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Three OTs detected by MASTER

ATel #5471; D. Denisenko, S. Shurpakov, E. Gorbovskoy, V. Lipunov, N. Tiurina, P. Balanutsa, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov, V. Yecheistov (Moscow State University, SAI), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova (Irkutsk State University), 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), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), P. Podvorotny, V. Shumkov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 15 Oct 2013; 07:53 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Transient, Variables

MASTER OT J193911.05+685135.0 - CV or flare star

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 19h 39m 11.05s +68d 51m 35.0s on 2013-10-13.56683 UT. The OT unfiltered magnitude is 16.7m (limit 19.9m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2011-10-02.53964 UT with unfiltered magnitude limit 19.9m.

There is nothing at this position in 1RXS, 2MASS, USNO-B, GCVS and AAVSO VSX. This area of sky in Draco is not covered by SDSS, CRTS and GALEX. There is a star at 1" from the OT in GSC 2.3.2 with the coordinates 19 39 10.957 +68 51 36.15 and infrared magnitude N=18.41 from the 1996-07-07 Palomar plate. Color-combined (BRIR) finder chart is posted at http://master.sai.msu.ru/static/OT/J193911+685135-BRIR5x5.jpg

From the IR detection in GSC 2.3.2 it is not clear if the OT is a flaring red dwarf or a dwarf nova which was in another outburst in July 1996. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/193911.05685135.0.png

MASTER OT J191617.64+691356.4 - possible CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 19h 16m 17.64s +69d 13m 56.4s on 2013-10-14.53574 UT. The OT unfiltered magnitude is 18.5m (limit 19.8m). The OT is seen in 3 images. We have reference image without OT on 2011-10-04.57041 UT with unfiltered m_lim=19.7.

Nothing is present at this position in 1RXS, GALEX, USNO-B, 2MASS, GCVS and AAVSO VSX. This area of sky in Draco is not covered by SDSS and CRTS. There is a faint star 1" from the OT in GSC 2.3.2 with the coordinates 19 16 17.550 +69 13 57.49 and red magnitude F=20.32 from 1991-06-19 Palomar plate. It is not visible on blue and infrared plates. Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J191617+691356-BRIR5x5.jpg

The OT is likely a cataclysmic variable in outburst. Spectral observations are required. Discovery and reference images: http://master.sai.msu.ru/static/OT/191617.64691356.4.png

MASTER OT J020438.08+503820.2 - new CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 02h 04m 38.08s +50d 38m 20.2s on 2013-10-14.79626 UT. The OT unfiltered magnitude is 16.9m (limit 18.6m). The OT is seen in 3 images. We have reference image without OT on 2011-11-29.58204 UT with unfiltered m_lim=20.0.

The OT at quiescence is identical to the star USNO-B1.0 1406-0053260 (02 04 38.203 +50 38 21.41 B1=N/A R1=19.29 B2=20.68 R2=19.97). Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J020438+503820-BRIR.jpg (10'x10' field of view).

There is nothing at this position in 1RXS, GALEX, 2MASS, GCVS and AAVSO VSX. This area of sky in Perseus is not covered by SDSS and CRTS. The nearest star in catalogues and on DSS plates is 1.7" from the OT: USNO-B1.0 1406-0053260 (02 04 38.203 +50 38 21.41 B1=N/A R1=19.29 B2=20.68 R2=19.97). The proper motions in USNO-B catalogue (-88, -220 mas/yr) are likely erroneous. It is not clear if this star is the quiescent counterpart to the OT. If not, the outburst amplitude is more than 5m.

Follow up observations are required. Discovery and reference images: http://master.sai.msu.ru/static/OT/020438.08503820.2.png

Outburst of a poorly studied CV

We also report the detection by MASTER-Tunka of the known variable in Kepler field KIS J192604.22+393553.6 (Scaringi et al., MNRAS Vol. 428, pp. 2207-2215, 2013) at 17.0m on 2013-10-14.52944 UT. It was bright on the 1982-05-23 Quick-V plate (18.0m). Detection and reference images: http://master.sai.msu.ru/static/OT/192604.25393553.3.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net