MASTER: 2 dwarf novae and bright comet discovery in Gagarin's day

ATel #7374; P. Balanutsa, O. Gress (ISU), V. Lipunov, E. Gorbovskoy (Lomonosov MSU), D. Buckley (SAAO), S. Antipin, N. Tiurina, V. Kornilov, V. Chazov, E. Popova, V. Vladimirov, S. Shumkov, S. Shurpakov (Lomonosov Moscow State University, SAI), S. Potter, A. Kniazev, M. Kotze (The South African Astronomical Observatory), O. Gress, K. Ivanov, N. Budnev, S. Yazev, V. Poleshchuk, E. Konstantinov, O. Chuvalaev (Irkutsk State University), A. Tlatov, D. Dormidontov, V. Senik, A. Parkhomenko, (Kislovodsk solar station of the Pulkovo observatory RAS), V. Yurkov, Y. Sergienko, A. Gabovich (Blagoveshchensk Educational University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University)
on 12 Apr 2015; 16:30 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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12 April 2015

54 years ago Russian Yuriy Gagarin was the first man who started to the Space from the Earth. The USSR presents to all World this great holiday, discovered the Space for the peace human's work

MASTER OT J131131.16-492031.3 discovery - new Dwarf Nova flare

MASTER-SAAO auto-detection system ( Lipunov et al., Advances in Astronomy, MASTER Global Robotic Net, 2010 ) discovered OT source at (RA, Dec) = 13h 11m 31.16s -49d 20m 31.3s on 2015-04-11.97669 UT.

The OT unfiltered magnitude is 19.0m (the limit is 19.4m).

The OT is seen in 3 images. We have reference image without OT on 2015-01-18.02954 UT with unfiltered magnitude limit 19.8m.
There is no any source inside 5" in VIZIER database (so the amplitude is more then 3m => DN). There is no minor planet at this place.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/131131.16-492031.3.png

Spectral observations are required.

MASTER OT J131647.96-293542.2 discovery - Dwarf Nova flare

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 13h 16m 47.96s -29d 35m 42.2s on 2015-04-12.01101UT.

The OT unfiltered magnitude is 18.0m (the limit is 19.7m). The OT is seen in 3 images. We have reference image with marginally seen OT (m~20.2) on 2015-02-18.01866 UT with 19.9 unfiltered magnitude limit.

There is 1 flare of this MASTER OT with 8m amplitude in CRTSurvey (Vmag~11.8) about 5.5years ago , but this is not real flare, because its duration was 24 min (from 19.8(V) to 11.8), but there is no red magnitudes for UVCet type. So the possible most probable classification for current flare is Dwarf Nova flare.

Spectral observations are required.

The discovery and reference MASTER images are available at http://master.sai.msu.ru/static/OT/MASTERJ131647.96-293542.2.jpg

COMET C/2015 G2 (MASTER)

The MASTER-SAAO (SAAO, Sutherland) auto detection system discovered very bright comet (11 mag) (MPEC 2015-G28). The color image is available at http://www.pereplet.ru/lipunov/343.html#343

Follow up observations are required.

MASTER Global Robotic Net