Two New Cataclysmic Variables detected by MASTER

ATel #6615; N. Tiurina, S. Shurpakov, P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov, E. Popova (Lomonosov Moscow State University, SAI), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (Irkutsk State University), A. Tlatov, D. Dormidontov, V. Senik, A. Parkhomenko (Kislovodsk Solar Station of Pulkovo Observatory), V. Yurkov, A. Gabovich, Y. Sergienko, E. Sinyakov (Blagoveshchensk Educational University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), V. Shumkov (MASTER team member)
on 24 Oct 2014; 11:45 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J203933.97+260924.5 - new CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 20h 39m 33.97s +26d 09m 24.5s on 2014-10-14.51801 UT. The OT unfiltered magnitude is 16.8m (limit 18.2m). The OT is seen in 18 images. There is no minor planet at this place. We have reference image without OT on 2011-08-20.70796 UT with unfiltered magnitude limit 18.6m. There was a previous outburst to 16.6m in MASTER-Tunka data on 2012-11-24.481 and 2012-11-24.512 UT.

The OT at quiescence is identical to the blue star SDSS J203933.92+260925.0 (u=19.89 g=19.93 r=19.46 i=19.14 z=18.92) = USNO-B1.0 1161-0507572 (20 39 33.92 +26 09 25.2 B1=16.76 R1=17.00 B2=20.57 R2=19.69 I=17.61). It was in outburst on 1956 May 05 blue and red POSS-I plates. Comparison of 1956 and 1989 blue Palomar plates is posted at http://master.sai.msu.ru/static/OT/J203933+260924-POSS-Blue.jpg (5'x5' FOV). The object is not present in 1RXS, GCVS and AAVSO VSX. This area of sky in Vulpecula is not covered by NEAT, CRTS and GALEX.

Based on the blue color, amplitude of variability and previous outbursts, MASTER OT J203933.97+260924.5 is a new cataclysmic variable (dwarf nova). Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/203933.97260924.5.png

MASTER OT J073601.27+135954.0 - new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 07h 36m 01.27s +13d 59m 54.0s on 2014-10-24.02365 UT. The OT unfiltered magnitude is 16.1m (limit 19.5m). The OT is seen in 11 images. There is no minor planet at this place. We have reference image without OT on 2011-01-06.82174 UT with unfiltered magnitude limit 19.8m.

The object at quiescence is identical to USNO-B1.0 1039-0144181 (07 36 01.293 +13 59 53.85 pmRA=-10 pmDE=-6 B1=19.67 R1=18.92 B2=20.69 R2=19.46 I=N/A). Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J073601+135954-BRIR.jpg (2x zoom). Nothing is present at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Gemini is not covered by SDSS and GALEX.

Palomar/NEAT project has 80 available images of this area on 30 nights from 1997 Dec. 29 to 2006 Dec. 21. The star was in outbursts on 2000 Dec. 03-04, 2002 Mar. 19 and 2003 Jan. 23. Those outbursts were fainter than the current detection by MASTER. There is another possible outburst to 18.2m on 2013 May 01 in Mount Lemmon Survey data.

Based on the amplitude of variability (about 4m) and previous fainter outbursts, MASTER OT J073601.27+135954.0 is a new cataclysmic variable (dwarf nova). The current outburst may be a superoutburst. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/073601.27135954.0.png

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