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Two bright new CVs detected by MASTER

ATel #4506; D. Denisenko, E. Gorbovskoy, V. Lipunov, P. Balanutsa, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, 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 (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), V. Shumkov, S. Shurpakov, P. Podvorotny, (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (Observatorio Astronomico Felix Aguilar; OAFA)
on 22 Oct 2012; 08:21 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Cataclysmic Variable

MASTER OT J081110.46+660008.5 - new bright CV with outburst amplitude 8m

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 08h 11m 10.46s +66d 00m 08.5s on 2012-10-20.79277 UT. The OT unfiltered magnitude is 14.1m (limit 18.9m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2011-10-07.76701 UT with unfiltered magnitude limit 18.5m.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/081110.46660008.5.png

The OT is identical to the star SDSS J081110.43+660010.3 with the following magnitudes: u=22.42 g=22.07 r=22.11 i=22.16 z=22.26. The new variable has also an UV counterpart with two entries in GALEX catalog: GALEX J081110.7+660013 (FUV=21.31+/-0.49 NUV=20.84+/-0.26) and GALEX J081110.8+660013 (FUV=21.71+/-0.48 NUV=21.18+/-0.29). The star is showing variability on blue Palomar plates. According to USNO-B1.0, it had B=18.98 on 1955-01-28 POSS-I plate and B=20.51 on 1997-02-05 POSS-II plate.

Nothing is present at this position in GCVS and AAVSO VSX. No previous outbursts were detected by Catalina Sky Survey. This area was not covered by NEAT. The comparison of MASTER-Amur, DSS red and SDSS color images is uploaded to http://master.sai.msu.ru/static/OT/081110.4+660008.jpg

Based on the outburst amplitude and blue color (SDSS g-r=-0.04, r-i=-0.05) we conclude that MASTER OT J081110.46+660008.5 is a new cataclysmic variable, most likely a dwarf nova of WZ Sge (UGWZ) type. Follow up observations are required.

MASTER OT J182122.64+283211.4 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 18h 21m 22.64s +28d 32m 11.4s on 2012-10-21.43522 UT. The OT unfiltered magnitude is 16.0m (limit 18.4m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-08-21.62466 UT with unfiltered magnitude limit 18.8m.

There is nothing at this position in USNO-B1.0, GSC 2.3.2, 2MASS, 1RXS and GCVS catalogs as well as in AAVSO VSX. No previous outbursts were detected on 9 images obtained by Palomar/NEAT during 3 different nights in 1997-1998. This area is not covered by SDSS, GALEX and CSS.

There is a faint star (magnitude ~21) on blue Palomar plates obtained on 1951-07-10 and 1990-07-22. Comparison of POSS-I and POSS-II plates is posted at http://master.sai.msu.ru/static/OT/J182122+283211-anim-DDS-B.gif

The galactic latitude is +19 deg. Based on the amplitude of variability we suggest that MASTER OT J182122.64+283211.4 is likely 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/182122.64283211.4.png

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