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Two Large Amplitude CVs in Draco discovered by MASTER

ATel #5974; P. Balanutsa, V. Vladimirov, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, 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 12 Mar 2014; 15:16 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

Subjects: Optical, Cataclysmic Variable, Transient

MASTER OT J171921.40+640309.8 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 17h 19m 21.40s +64d 03m 09.8s on 2014-03-10.58719 UT. The OT unfiltered magnitude is 15.6m (limit 18.0m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-10-17.57058 UT with unfiltered magnitude limit 19.6m.

The OT at quiescence is identical to the blue star SDSS J171921.26+640311.0 (u=21.41 g=21.29 r=21.25 i=21.30 z=21.93) = USNO-B1.0 1540-0207100 (17 19 21.186 +64 03 10.20 pmRA=-12 pmDE=-32 B1=16.32 R1=16.65 B2=21.32 R2=20.19 I=N/A). The star was in outburst on POSS-I blue and red plates taken on 1953 June 09 and at quiescence elsewhere. Comparison of the 1st and 2nd epoch Palomar blue plates is uploaded to http://master.sai.msu.ru/static/OT/J171921+640309-POSS-B.jpg (5'x5' FOV).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. No previous outbursts were detected by CSS. Based on the amplitude of variability (~6m) MASTER OT J171921.40+640309.8 is a new cataclysmic variable, most likely a dwarf nova of UGSU (SU UMa) type in superoutburst. SDSS colors suggest the short orbital period. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/171921.40640309.8.png

MASTER OT J200904.69+825153.6 - new large-amplitude CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 20h 09m 04.69s +82d 51m 53.6s on 2014-03-10.59524 UT. The OT unfiltered magnitude is 15.6m (limit 17.7m). The OT is seen in 5 images. There is no minor planet at this place. We have reference image without OT on 2012-09-24.49289 UT with unfiltered magnitude limit 18.0m.

There is a faint (~22.5m) blue star at the position of the OT on the sum of digitized Palomar plates. It is not present in USNO-B and GSC. Color-combined DSS finder chart (sum of 3 BRIR images) is uploaded to http://master.sai.msu.ru/static/OT/J200904+825153-BRIR5x5.jpg (2x zoom).

The object has an UV counterpart GALEX J200904.5+825153 with two entries in GALEX catalogue: FUV=18.01, NUV=18.05 and FUV=18.71, NUV=18.73. 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 CSS. Based on the amplitude of variability (~7m) MASTER OT J171921.40+640309.8 is a new cataclysmic variable, likely a dwarf nova of UGSU (SU UMa) or UGWZ (WZ Sge) type in superoutburst. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/200904.69825153.6.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net