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Two new CVs detected by MASTER

ATel #5217; S. Shurpakov, D. Denisenko, V. Lipunov, E. Gorbovskoy, P. Balanutsa, N. Tiurina, V. Kornilov, A. Belinski, 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), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova (Irkutsk State University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk solar station of the Pulkovo observatory RAS), P. Podvorotny, V. Shumkov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 20 Jul 2013; 10:14 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Transient

MASTER OT J223315.51+393539.5 - CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 22h 33m 15.51s +39d 35m 39.5s on 2013-07-12.65778 UT. The OT unfiltered magnitude is 17.6m (limit 18.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-08-18.69272 UT with unfiltered magnitude limit 19.2m.

There is a faint star within 1.5" of the OT on the sum of digitized Palomar plates. It is present in GSC 2.3.2 with coordinates 22 33 15.419 +39 35 38.66 and jmag=22.00. Color-combined (BRIR) DSS image is uploaded to http://master.sai.msu.ru/static/OT/J223315+393539-BRIR5x5.jpg

There is nothing at this position in 1RXS, USNO, 2MASS, GCVS and AAVSO VSX. This area of sky in Lacerta is not covered by SDSS. No previous outbursts were detected by Catalina Sky Survey.

Based on the amplitude of variability (~4m) we suggest that MASTER OT J223315.51+393539.5 is a new cataclysmic variable (dwarf nova in outburst). Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/223315.51393539.5.png

MASTER OT J023406.06+384142.4 - new bright CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 02h 34m 06.05s +38d 41m 42.4s on 2013-07-19.98779 UT. The OT unfiltered magnitude is 15.6m (limit 18.7m). The OT is seen in 12 images. There is no minor planet at this place. We have reference image without OT on 2013-02-06.66060 UT with unfiltered magnitude limit 17.9m.

There is a faint star at this position on Palomar plates with a detectable proper motion between 1st and 2nd epochs. It is present in GSC 2.3.2 with coordinates 02 34 06.164 +38 41 41.24 and magnitudes Fmag=19.60, jmag=20.55. Color-combined (BRIR) DSS image is uploaded to http://master.sai.msu.ru/static/OT/J023406+384142-BRIR.jpg (10'x10' FOV). New object is located 2.5' south of bright star HD 15865 (HIP 11947) with B=7.78, V=6.67.

There is nothing at this position in 1RXS, GALEX, USNO, 2MASS, GCVS and AAVSO VSX. This area of sky in Andromeda is not covered by SDSS. No previous outbursts brighter than ~18m were detected by Catalina Sky Survey. The object was observed by Palomar/NEAT project on 5 different nights from 2001 Dec. 23 to 2002 Nov. 25. A total of 14 images were obtained. The star has brightened to ~17.5m on 2002 Nov. 15 but was not visible on other 4 nights to the limiting mag ~20.

Based on the amplitude of variability (~5m) we suggest that MASTER OT J023406.06+384142.4 is a new cataclysmic variable, 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/023406.06384142.4.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net