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New transcient, perhaps a nova

PostPosted: Fri Jun 23, 2017 5:20 pm
by Francois Teyssier
ATEL #10523 ATEL #10523

Title: ASAS-SN Discovery of a Possible Galactic Nova ASASSN-17ib 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), Subo Dong (KIAA-PKU)
Queries: stanek.32@osu.edu
Posted: 23 Jun 2017; 16:20 UT
Subjects:Optical, Nova

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN,
<a href="http://adsabs.harvard.edu/%61bs/2014ApJ...788...48S">Shappee
et al. 2014</a>), using data from the quadruple 14-cm "Brutus"
telescope in Haleakala, Hawaii, we detect a bright, new transient
source, possibly a classical nova (could also be a bright CV), near
the Galactic plane

Object RA (J2000) DEC (J2000) Gal l (deg) Gal b (deg)
Disc. UT Date Disc. V mag
ASASSN-17ib 18:31:45.918 -14:18:55.57 17.969 -2.232
2017-06-23.47 12.5

ASASSN-17ib was discovered in images obtained on UT 2017-06-23.47 at
V~12.5, and it is also detected in several earlier epochs, starting at

UT 2017-06-19.41 at V~14.7. We do not detect (V>17.1) this object in
subtracted images taken on UT 2017-06-13.21 and before.

Using newly released <a href=https://asas-sn.osu.edu/>ASAS-SN Sky
Patrol</a> light curve interface (<a
href=https://arxiv.org/abs/1706.07060>Kochanek et al. 2017, PASP,
submitted)</a>, we have retrieved aperture photometry time series at the

location of ASASSN-17ib in the last 20 days, and the resulting light
curve can be seen <a
href=https://asas-sn.osu.edu/light_curve/29a5a1e8-e6cf-4e01-93d4-fcbbbdd0f198>here</a>.

No previous outbursts are detected at the position of ASASSN-17ib
since ASAS-SN started observing this location in February 2015.

Follow-up observations, especially 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).

ASAS-SN Sky Patrol Light Curve of ASASSN-17ib :
https://asas-sn.osu.edu/light_curve/29a ... bbbdd0f198

Re: New transcient, perhaps a nova

PostPosted: Wed Jun 28, 2017 10:49 pm
by Paolo Berardi
Hi all, with Atel #10527 the nova was confirmed as He/N type. Atel brings a link to a beautiful spectrum taken with the 2m RCC telescope at Rozhen observatory (Bulgaria).

http://www.astronomerstelegram.org/?read=10527

I just tried to observe it between two buildings (unfortunately I have some houses obstructing the horizon there) but a shower forced me to quickly close the observatory.

Only 50 sec exposure with a very strong turbulence. Anyway, the "super-noisy" profile shows a strong h-alpha emission line and weaker h-beta and h-gamma lines.

The nova is very bright. I measured an approximate unfiltered mag value of 11.3. Try to observe if you have a chance.

The guider view:

Image

The very noisy spectrum:

Image

Paolo

Re: New transcient, perhaps a nova

PostPosted: Thu Jun 29, 2017 6:48 pm
by Francois Teyssier
Congratulations for the trial
It should decline fastly
François

Re: New transcient, perhaps a nova

PostPosted: Thu Jun 29, 2017 9:07 pm
by etienne bertrand
Good detection, for 50s it's a very good results.

Re: New transcient, perhaps a nova

PostPosted: Thu Jun 29, 2017 11:52 pm
by umberto sollecchia
Bonjour à tous, placez le profil de nova observée sur 29/06/2017 dans des conditions météorologiques non optimales.Umberto

Profilo nova.png
Profilo nova.png (6.8 KiB) Viewed 7648 times

Re: New transcient, perhaps a nova

PostPosted: Fri Jun 30, 2017 8:41 am
by Joan Guarro Flo
Umberto e Paolo,

You have done a good detection job, congratulations!

Un abbraccio, Joan.

Re: New transcient, perhaps a nova

PostPosted: Fri Jun 30, 2017 8:46 am
by umberto sollecchia
Un grand merci Joan, un accueil chaleureux .Umberto

Re: New transcient, perhaps a nova

PostPosted: Fri Jun 30, 2017 8:54 am
by Forrest Sims
Greetings!
I had pretty good conditions tonight and I was able to capture 7x500sec of asassn17hx data with a C11HD with LISA and an Atik414ex. I used HD204754 as a Reference star.

Re: New transcient, perhaps a nova

PostPosted: Fri Jun 30, 2017 6:42 pm
by Paolo Berardi
Thank you all for your comments! Umberto, Woody, very nice spectra (LISA spectrum is fantastic). Joan, I think you could try with your echelle spectrographs. As soon as you can because the nova is now very bright (François tell us that it should fade quickly).

Yesterday many clouds were passing in the sky during the observation (as for Umberto, we live in the same city). Simultaneous photometry returned V mag 11.43 (average value).

Image

I tried the line identification (some lines are discribed in the related ATels). The three weak emission lines with question mark resemble to me the Fe II multiplet 42 (hybrid nova?) but there are other possibile lines:

1) He I 4922 and/or Fe II 4924 (42)
2) He I 5016 and/or Fe II 5018 (42)
3) Mg I 5178 and/or Fe II 5169 (42)

What do you think?

Paolo

Re: New transcient, perhaps a nova

PostPosted: Sat Jul 01, 2017 1:26 pm
by Francois Teyssier
Congratulations Poalo, Umberto and Woody!
Page in ARAS database : http://www.astrosurf.com/aras/Aras_DataBase/Novae/2017_NovaSct2017.htm

The relation between the mass of the white dwarf, the mass and velocity of the ejecta, the spectral type and the rapidity class is discribed
by Della Valla & Livio http://iopscience.iop.org/article/10.1086/306275/pdf

Name in the header:
Please use ASASSN-17hx or nova sct 2017

All the best,

François
(Quebec City)