New Nova in Centarus

[Merlin66]

One for us......

The Astronomer's Telegram
http://www.astronomerstelegram.org

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ATEL #10387 ATEL
#10387

Title: ASAS-SN Discovery of A Likely Galactic Nova ASASSN-17gk on
the Rise
Author: K. Z. Stanek, C. S. Kochanek (OSU), L. Chomiuk, J. Strader
(MSU), J. S. Brown, T. W.-S. Holoien, J. V. Shields, T. A.
Thompson
(OSU), B. J. Shappee (Hubble Fellow, Carnegie
Observatories), J. L.
Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong,
S. Bose,
Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers
Observatory)
Queries: stanek.32@osu.edu
Posted: 18 May 2017; 00:49 UT
Subjects:Optical, Nova

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or

"Assassin"), using data from the quadruple 14-cm "Cassius" telescope in
CTIO, Chile, we detect a very bright, new transient source, most likely a
classical nova, near the Galactic plane

Object RA (J2000) DEC (J2000) Gal l (deg) Gal b (deg)
Disc. UT Date Disc. V mag
ASASSN-17gk 13:20:55.32 -63:42:18.5 306.187 -1.02
2017-05-17.28 10.9

ASASSN-17gk was discovered in images obtained on 2017-05-17.28 at V~10.9,
but it has been present in ASAS-SN data since 2017-04-25.08 (V~13.3), with
significant shorter-timescale variability (V~11.6 on
2017-04-28.11 and V~12.05 on 2017-05-04.19). We do not detect (V>17.4)

this object in subtracted images taken on UT 2017-04-23.16 and before. No
previous outbursts are detected at this location since ASAS-SN started
observing it in February 2016.

Follow-up observations, especially multi-band photometry and spectroscopy,
are strongly encouraged.

We thank Las Cumbres Observatory and its staff for their continued support
of ASAS-SN. ASAS-SN is funded in part by the Gordon and Betty Moore
Foundation through grant GBMF5490 to the Ohio State University, NSF grant
AST-1515927, the Mt. Cuba Astronomical Foundation, the Center for Cosmology
and AstroParticle Physics (CCAPP) at OSU, and the

Chinese Academy of Sciences South America Center for Astronomy (CASSACA).

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Password Certification: Krzysztof Stanek (stanek.32@osu.edu)
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[Andrew Pearce]

Hi All

I've just visually observed this nova suspect at mag 10.9 on May 18.43 UT.

Regards
Andrew Pearce

[Terry B]

:rain::rain::rain::rain::rain::rain ::rain:
Just typical

[bojan]

Weekend looks hopeful....

[cometcatcher]

I think this might be it. I think. The reddish one. It's lost in the stars. 10" F4 newt, Full spectrum Canon 1100D, 9x30 secs, no filter.

[Merlin66]

Yep, you got it!
Your field matches well to the given position and the UCAC star catalogue.

[cometcatcher]

Thanks for the confirmation Ken! I knew I had to be close.

[bojan]

I also managed to shoot it last night....unfortunately focus was off a bit, I didn't wait long enough for my Rubinar to cool down properly.

[cometcatcher]

Nice one Bojan!

[bojan]

Tonight's one is much better (Rubinar10_1000, Canon 450D FSM, L-Pro filter, 16x64sec, from Melbourne).
The other image is screen dump from CdC, UCAC3 catalog, with Nova marked.

[Terry B]

I had a small break in cloud to take BVRI images. Just 1min/exp and no chance of a spectrum. The pic is the V image.
V mag = 10.99

[Terry B]

I had more clear skies last night and was able to take more images of this nova. I also took a simultaneous spectra but the spectrograph on my scope at the moment is my LHIRESIII. It is only useable on bright stars but I thought I would try and use it.
V mag was 11.16 so it had dimmed a little since the previous night. The spectrograph is centered on Ha frequency at the moment which is in the R filter band using photometry filters. It measured R=10.0
I only took 15 mins of exposure for the spectra but could identify the Ha emission. The background continuum was virtually not visible. The S/N is low but I can still measure the expansion velocity at about 1000km/s.