MASTER-SAAO: 2 optical transients

ATel #7897; P. Balanutsa, O. Gress, V. Lipunov (Lomonosov MSU), D. Buckley (SAAO), E. Gorbovskoy, V. Kornilov, N. Tiurina, A. Kuznetsov, V. Chazov, D. Vlasenko, I. Gorbunov (Lomonosov Moscow State University, Sternberg Astronomical Institute), S. Potter, M. Kotze (South African Astronomical Observatory),R. Rebolo, M. Serra-Ricart , N. Lodieu, G. Israelian (The Instituto de Astrofisica de Canarias), N. M. Budnev, K. Ivanov (Applied Physics Institute, Irkutsk State University), A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of the Pulkovo Observatory), V. Krushinski, I. Zalozhnykh (Ural Federal University), Yu. Sergienko, A. Gabovich, V. Yurkov (Blagoveschensk Educational State University)
on 9 Aug 2015; 23:05 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J042736.41-494347.2 detection - possible dwarf nova outburst, Ampl>3.6

MASTER-SAAO auto-detection system ( Lipunov et al., Advances in Astronomy, MASTER Global Robotic Net, 2010 ) discovered OT source at (RA, Dec) = 04h 27m 36.41s -49d 43m 47.2s on 2015-08-09.10317 UT.
The OT unfiltered magnitude is 17.6m (the limit is 20.0m).

The OT is seen in 3 images (2015-08-09.10317, 09.11108, 09.118969UTT). There is no minor planet at this place.

We have reference image with marginally seen OT on 2015-01-16.91642 UT with 20.4 unfiltered magnitude limit. We have reference image without OT on 2014-12-27.88662 (m_lim=19.5). We have images with OT on 2015-03-29.336652UT with m_OT=18.0 and on 2015-02-23.825843 with m_OT=18.3 . There is a star in USNO-A2,B1 with R=18.0-21.37 and B=19.9-20.84. So we can suggest the dwarf nova outburst with ampl. > 3.6

Spectral observations are required.

The discovery and reference images are available at: http://observ.pereplet.ru/images/MASTEROTJ042736.41-494347.2.png

MASTER OT J160701.23-143446.8 detection - R CrB possible flash

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 16h 07m 01.23s -14d 34m 46.8s on 2015-08-08.78144 UT.

The OT unfiltered magnitude is 17.7m (the limit is 19.8m). The OT is seen in 6 images. There is no minor planet at this place.

We have reference image without OT on 2015-04-27.87244 UT with unfiltered(m_lim=19.3), and on 2015-02-02.08979 with m_lim=18.8UT. There is a star from Catalogue enriched with R CrB stars (Tisserand, 2012) in 0.487".

Spectral observations are required.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/160701.23-143446.8.png

MASTER Global Robotic Net