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Three OTs detected by MASTER

ATel #4865; S. Shurpakov, P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Yecheistov, D. Zimnukhov (Moscow State University, SAI), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov, A. Punanova (Ural Federal University), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova, (Irkutsk State University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk solar station of the Pulkovo observatory RAS), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov (Blagoveshchensk Educational University), P. Podvorotny, V. Shumkov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 6 Mar 2013; 18:25 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Star, Transient, Variables

MASTER OT J034105.82+072250.1 - new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 03h 41m 05.82s +07d 22m 50.1s on 2013-03-03.70317 UT. The OT unfiltered magnitude is 16.9m (limit 18.8m). The OT is seen in 2 images. We have reference image without OT on 2013-01-03.848 UT with unfiltered mag. limit 19.7.

There is nothing there on 9 DSS plates and SDSS images (m_lim~23). Object is not present in 1RXS, GALEX, USNO-B, GSC, 2MASS, GCVS and AAVSO VSX. No outbursts were detected by CSS. This field was observed by NEAT on 40 nights from 1997 Nov. 30 to 2006 Dec. 24 with 111 images. Object was in outburst on 3 images of 2001 Oct. 29 and at quiescence otherwise.

Based on amplitude of variability (~6m) and previous outburst we conclude that MASTER OT J034105.82+072250.1 is a CV, most likely dwarf nova of SU UMa type. Follow up observations are encouraged. The discovery and reference images are available at http://master.sai.msu.ru/static/OT/034105.82072250.1.png

MASTER OT J053714.75+155418.4 - new CV?

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 05h 37m 14.75s +15d 54m 18.4s on 2013-03-05.57793 UT. The OT unfiltered magnitude is 16.0m (limit 17.8m). The OT is seen in 17 images. We have reference image without OT on 2012-10-19.65986 UT with unfiltered mag. limit 18.4.

There is nothing at this position in 1RXS, GCVS and AAVSO VSX. The OT is identical to USNO-B1.0 1059-0078748 (05 37 14.783 +15 54 18.07 pmRA=-18 pmDE=8 B1=19.58 R1=19.04 B2=20.21 R2=18.77 I=16.13) and 2MASS 05371478+1554172 (J=16.97 H=16.35 K=15.80). This area is not covered by SDSS and GALEX. DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J053714+155418-BRIR5x5.jpg

The star varies by ~2m between POSS-I and II plates. 13 NEAT images were taken on 4 nights in 2001. Object was bright on 2001 Jan. 01 images. CSS is showing variability from 16.3m to 18.3m. The star was bright on 2008 Dec. 20, 2009 Nov. 22 and 2011 Oct. 22. MASTER-Amur has the object at V=15.4 and V=15.5 on 2011 Mar. 24.466 and 24.498 UT.

Based on the presence of previous outbursts we suggest that MASTER OT J034105.82+072250.1 is likely a cataclysmic variable. Spectral and photometric observations are required. The discovery and reference images are available at http://master.sai.msu.ru/static/OT/053714.75155418.4.png

MASTER OT J145836.64+274125.0 - flare star of UV Ceti type

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 14h 58m 36.64s +27d 41m 25.0s on 2013-03-05.72086 UT. The OT unfiltered magnitude is 16.1m (limit 18.3m). The OT is seen in 3 images. We have reference image without OT on 2013-02-07.710 UT with unfiltered mag. limit 18.6.

OT is showing fast variability between the images obtained with ~100 sec interval (60s exp. + 36s readout). It was not visible on images taken 45 minutes earlier.

Obs. date  Exp.start Mag. 
2013-03-05 16:30:06 <18.3 
2013-03-05 16:31:46 <18.3 
2013-03-05 16:33:23 <18.3 
2013-03-05 17:14:41  16.67+-0.13 
2013-03-05 17:16:20  15.86+-0.07 
2013-03-05 17:18:02  16.14+-0.09

The object is identical to 2MASS 14583655+2741283 (offset 3", epoch 1999 May 22, J=15.24 H=14.60 K=14.21), SDSS J145836.57+274127.3 (2", 2008 Apr. 13, r=21.90 i=19.22 z=17.38) and WISE J145836.61+274126.2 (1", W1=13.81 W2=13.57 W3=13.14). Spectral class is M9 according to West et al., 2011, Astron. J., 141, 97. Object is not present in 1RXS, GALEX, GCVS and AAVSO VSX. No flares were detected by CSS in 2005-2012.

Based on the short rise time, amplitude and color we conclude that MASTER OT J145836.64+274125.0 is a new flaring star of UV Ceti type. Follow up observations are encouraged. The discovery and reference images are available at http://master.sai.msu.ru/static/OT/145836.64274125.0.png

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