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MASTER Discovery of Two Possible Cataclysmic Variables

ATel #6855; P. Balanutsa, A. Rufanov, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov (Lomonosov Moscow State University, SAI), A. Tlatov, D. Dormidontov, V. Senik, A. Parkhomenko (Kislovodsk Solar Station of Pulkovo Observatory), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (Irkutsk State University), V. Yurkov, A. Gabovich, Y. Sergienko, E. Sinyakov (Blagoveshchensk Educational University), V. Shumkov, S. Shurpakov (MASTER team members)
on 29 Dec 2014; 17:06 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

Subjects: Optical, Cataclysmic Variable, Transient

MASTER OT J201013.27+203202.6 - possible new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 20h 10m 13.27s +20d 32m 02.6s on 2014-12-27.64074 UT. The OT unfiltered magnitude is 16.4m (limit 18.0m). The OT is seen in 5 images. There is no minor planet at this place. We have reference image without OT on 2011-09-13.74319 UT with unfiltered magnitude limit 18.7m.

The OT is identical to the star USNO-B1.0 1105-0497184 (B1=N/A R1=N/A B2=16.02 R2=16.59) = 2MASS J20101330+2032018 (J=16.09 H=15.72). The star is showing obvious variability on the digitized Palomar plates. It was in the bright state on 1982-06-23 Quick-V plate (GSC 2.3.2 Vmag=17.53), 1991-09-08 red and 1994-06-15 infrared POSS-II plates and faint on the remaining six images, including 1951-09-20 POSS-I blue and red ones. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J201013+203202-BRIR5x5.jpg (2x zoom). Nothing is present at this position in 1RXS, GCVS and AAVSO VSX. This area of sky in Sagitta is not covered by SDSS, GALEX and Catalina Sky Survey.

Based on the amplitude of variability (more than 3m) and previous high states, MASTER OT J201013.27+203202.6 is a new cataclysmic variable. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/201013.27203202.6.jpg

MASTER OT J073304.39+155500.1 - possible new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 07h 33m 04.39s +15d 55m 00.1s on 2014-12-28.93227 UT. The OT unfiltered magnitude is 18.3m (limit 19.4m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2014-10-21.07273 UT with unfiltered magnitude limit 20.0m.

The OT at quiescence is identical to the star SDSS J073304.37+155501.7 (g=23.55 r=21.78 i=20.98). Nothing is present at this position in 1RXS, USNO-B, 2MASS, GCVS and AAVSO VSX. This area of sky in Gemini was observed by NEAT project on 33 different nights from 2000 Nov. 21 to 2006 Dec. 21 with about 100 images obtained. No outbursts were detected.

Based on the amplitude of variability (~3m), MASTER OT J073304.39+155500.1 is likely a new cataclysmic variable. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/073304.39155500.1.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net