New Active CV discovered by MASTER

ATel #5984; D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, P. Balanutsa, 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), 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. 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 17 Mar 2014; 10:44 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J193922.39+665346.0 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 19h 39m 22.39s +66d 53m 46.0s on 2014-03-13.71683 UT. The OT unfiltered magnitude is 15.3m (limit 17.4m). The OT is seen in 28 images. There is no minor planet at this place. We have reference image without OT on 2012-08-14.66741 UT with unfiltered magnitude limit 19.0m. Previous outbursts were detected by MASTER-Amur on 2012-10-12.553 and 12.580 UT (15.1m), 2013-01-27.845 and 27.877 UT (15.2m). The star was already bright on 2014-03-12.686 UT (15.0m) and 2014-03-12.717 UT (15.1m)

The OT at quiescence is identical to the blue star USNO-B1.0 1568-0205185 (19 39 22.449 +66 53 47.88 pmRA=6 pmDE=-6 B1=16.25 R1=16.25 B2=17.31 R2=18.66 I=17.89). It was bright on 1953-08-11 POSS-I blue and red plates. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J193922+665346-BRIR.jpg (10'x10' FOV). There is also an UV counterpart GALEX J193922.4+665347 (FUV=20.26+/-0.17 NUV=20.11+/-0.14). 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. The object was at quiescence during Palomar/NEAT observations on 2002 Sep. 23.

Based on the amplitude of variability (~4m), proper motion and UV detection, MASTER OT J193922.39+665346.0 is a new cataclysmic variable, most likely a dwarf nova in outburst. Follow up photometric observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/193922.39665346.0.png

We also note another blue object on the digitized Palomar plates with ultraviolet counterpart nearby, 83" west and 50" south of the OT: GALEX J193908.6+665256 (FUV=19.22+/-0.10 NUV=18.72+/-0.07) = USNO-B1.0 1568-0205140 (19 39 08.418 +66 52 56.09 pmRA=10 pmDE=16 B1=N/A R1=18.81 B2=18.41 R2=18.60 I=18.92). Its position is marked with an arrow on the 5'x5' finder chart http://master.sai.msu.ru/static/OT/J193922+665346-BRIR5x5.jpg (2x zoom). The second object has a larger UV-to-optical flux ratio compared to MASTER OT J193922.39+665346.0. It may be a hot white dwarf or another CV. Spectral observations of this blue object are also encouraged.

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