Three Optical Transients discovered by MASTER

ATel #5983; V. Vladimirov, D. Denisenko, V. Shumkov, V. Lipunov, E. Gorbovskoy, N. Tiurina, P. Balanutsa, 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, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 16 Mar 2014; 11:58 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J055348.98+482209.0 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 05h 53m 48.98s +48d 22m 09.0s on 2014-03-13.45517 UT. The OT unfiltered magnitude is 16.5m (limit 17.7m). The OT is seen in 4 images. There is no minor planet at this place. We have reference image without OT on 2012-10-19.76872 UT with unfiltered magnitude limit 18.7m.

Nothing is visible at this position on the digitized Palomar plates to the limiting magnitude ~21.5. Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J055349+482209-BRIR5x5.jpg (2x zoom).

There is nothing at this position in 1RXS, 2MASS, USNO-B, GSC, GCVS and AAVSO VSX. Object was at minimum light on 6 DSS plates and on 1 NEAT image of 2001 Dec. 23. This area of sky in Auriga is not covered by SDSS and CRTS. The object was likely detected in outburst during Carlsberg Meridian Catalog observations on 2002 Nov. 04 as CMC14 J055348.9+482209 (r'=16.62).

Based on the outburst amplitude (at least 5m), MASTER OT J055348.98+482209.0 is most likely a dwarf nova of 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/055348.98482209.0.png

MASTER OT J203824.15+174242.3 - new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 20h 38m 24.15s +17d 42m 42.3s on 2014-03-16.06113 UT. The OT unfiltered magnitude is 16.6m (limit 18.1m). The OT is seen in 3 images. We have reference image without OT on 2010-09-17.76663 UT with unfiltered m_lim=19.4.

The OT at quiescence is identical to the blue star USNO-B1.0 1077-0670813 (20 38 24.073 +17 42 43.19 B1=20.47 R1=N/A B2=20.19 R2=19.68 I=17.53). The star was is outburst on 1993-07-13 POSS-II infrared plate and at quiescence on other plates. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J203824+174242-BRIR5x5.jpg (2x zoom).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Delphinus is not covered by NEAT and CRTS.

Based on the amplitude of variability (~4m) and previous outburst, MASTER OT J203824.15+174242.3 is likely a new cataclysmic variable (dwarf nova). Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/203824.15174242.3.jpg

MASTER OT J213826.42+284622.4 - possible CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 21h 38m 26.42s +28d 46m 22.4s on 2014-03-16.07071 UT. The OT unfiltered magnitude is 16.9m (limit 17.8m). The OT is seen in 3 images. We have reference image without OT on 2012-09-15.87840 UT with unfiltered m_lim=19.8.

The OT it located within 1" of SDSS J213826.44+284621.4 (u=23.89 g=22.03 r=21.27 i=20.30 z=19.70). Though the object is catalogued as Galaxy in SDSS, close inspection of color-combined SDSS image shows it likely to be an extended blend of two stars - northern blue and southern red. There is also an UV counterpart GALEX J213826.5+284622 (FUV=17.71+/-0.06 NUV=17.62+/-0.03) in GALEX Data Release 5, but not in DR6/DR7.

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Cygnus is not covered by CRTS. Palomar/NEAT has 18 images on 5 different nights from 1998 Aug. 18 to 2002 Oct. 10. No outbursts were detected.

Based on the outburst amplitude (~4m) and UV detection, MASTER OT J213826.42+284622.4 is likely a cataclysmic variable (dwarf nova). Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/213826.42284622.4.jpg

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