Two OT discovered by MASTER

ATel #5898; V. Echeistov, P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, V. Kornilov, N. Tiurina, V. Chazov, A. Kuznetsov, (Moscow State University, SAI), 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. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational 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(OAFA)
on 18 Feb 2014; 11:21 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J065330.46+251150.9 - possible new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 06h 53m 30.46s +25d 11m 50.9s on 2014-02-16.45856 UT. The OT unfiltered magnitude is 15.9m (limit 17.5m). The OT is seen in 4 images. There is no minor planet at this place. We have reference image without OT on 2012-10-20.80635 UT with unfiltered magnitude limit 18.8m. The object was observed in outburst to 16.7m on 2011-01-31.625 UT by MASTER-Tunka but was not detected as a transient then.

The OT at quiescence is identical to the blue star USNO-B1.0 1151-0131099 (06 53 30.384 +25 11 50.27 B2=19.78 R2=19.20). Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J065330+251150-BRIR5x5.jpg (2x zoom). There is also an UV counterpart GALEX J065330.2+251150 (NUV=21.67+/-0.30).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. Object was at minimum light on 6 DSS plates and on 27 NEAT images from 10 different nights between 1997 Feb. 08 and 2002 Feb. 05. This area of sky in Gemini is not covered by SDSS and CRTS.

Based on the blue color, amplitude of variability (~4m) and previous detection, MASTER OT J065330.46+251150.9 is a cataclysmic variable (dwarf nova in outburst). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/065330.46251150.9.png

MASTER OT J054111.82+454054.9 - possible new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 05h 41m 11.82s +45d 40m 54.9s on 2014-02-16.45971 UT. The OT unfiltered magnitude is 15.8m (limit 17.7m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-10-18.64654 UT with unfiltered magnitude limit 18.6m.

The OT at quiescence is identical to the blue star USNO-B1.0 1356-0161028 (05 41 11.816 +45 40 56.27 pmRA=2 pmDE=30 B1=19.44 R2=20.16 I=18.38) = SDSS J054111.84+454055.3 (u=20.54 g=20.50 r=20.23 i=19.74 z=19.51).

There is nothing at this position in 1RXS, GALEX, 2MASS, GCVS and AAVSO VSX. Object was at minimum light on 6 DSS plates and on 4 NEAT images. This area of sky in Auriga is not covered by CRTS.

Based on the blue color and amplitude of variability (~5m), MASTER OT J054111.82+454054.9 is likely a dwarf nova of UGSU (SU UMa) type in superoutburst. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/054111.82454054.9.png

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