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Re: Nova Ophiuchi 2015

Posted: Fri Apr 17, 2015 3:18 am
by Tim Lester
Spectrum of Nova Oph for 2015-04-16 at R=1980.
According to the AAVSO light curve it is in decline with a Vmag of 11.
I am intrigued by the split lines in particular the two HeI lines at 6678 and 7065. Does this mean that the gases are expanding in two jets towards and away from us?
I would have thought that a symmetrical expansion would produce flat toped broad lines.
_novaoph2015_20150416_311_tlester.png
_novaoph2015_20150416_311_tlester.png (9.33 KiB) Viewed 8343 times
Tim

Re: Nova Ophiuchi 2015

Posted: Fri Apr 17, 2015 8:58 am
by umberto sollecchia
Bonjour à tous.
Dans mes trois observations, l'étoile de référence ne était pas exactement la hauteur de la nova.
Pour le dernière osservaziomne du 13-04-2015, je ai corrigé pour les différents atomsferica de transmission avec la fonction appropriée du programme ISIS.
Donc, je pense que le continuum est plus correct dans le dernier profil que je ai posté.
Sincèrement Umberto

Re: Nova Ophiuchi 2015

Posted: Fri Apr 17, 2015 6:35 pm
by Francois Teyssier
Looks to be very special, Tim
NovaOph2015_20150416_HeI.PNG
NovaOph2015_20150416_HeI.PNG (29.56 KiB) Viewed 8319 times
Steve will comment during the night

François

Re: Nova Ophiuchi 2015

Posted: Sat Apr 18, 2015 1:17 pm
by Olivier GARDE
Evolution of the nova since 72H is very fast.
Here's a graph with spectrum taken the 15th and the last taken this morning.

Image

Re: Nova Ophiuchi 2015

Posted: Sat Apr 18, 2015 7:10 pm
by Tim Lester
Nova Oph 2015 for the 18th compared to my last spectrum on the 16th.
I have converted both to flux using AAVSO data (had to extrapolate a bit for the 18th).
I find it very interesting that H beta and the HeI lines have retained their peak intensities
while Ha the continuum and all other lines have decreased.
_novaoph2015.png
_novaoph2015.png (12.04 KiB) Viewed 8288 times
Tim

Re: Nova Ophiuchi 2015

Posted: Sun Apr 19, 2015 1:37 am
by Christian Buil
Olivier, I confirm the very large change in the spectral profil (see also Tim's spectrum) on eShel spectrum (R=11000). The double peak structure on HeI 6678 A and 7065 A is also well visible (the flux on the continuum also change - global magnitude of the object). The comparison of 14 and 18 april observation:

Image

(the continuum is normalized to unity in the spectral range 6720-6800 A)

The very intense [OI] line at 5577 A (a quasi monochromatic shape) seem probable the 18.1 April, but the continuum is uncertain:

Image

The line at 5461 A is from the urban sky pollution (Hg line)

... the problem is the very bad observation condition the 18 April in Toulouse (bright sky (haze) and absorption)... the sky image 30 minutes after nova observation (!):

Image

Christian

Re: Nova Ophiuchi 2015

Posted: Tue Apr 21, 2015 8:22 am
by Jacques Montier
Hello,

Nova Ophiuci spectrum on 2015/04/20 with Alpy600.
The target was rather low at 3hUT : 19° in Brittany (France)
20150420_novaoph.png
20150420_novaoph.png (48.94 KiB) Viewed 8165 times
Regards,

Re: Nova Ophiuchi 2015

Posted: Tue Apr 21, 2015 8:50 pm
by umberto sollecchia
Bonsoir à tous, je apporte un nouveau profil de la nouvelle. L'observation a été effectuée dans la nuit du 21/04/2015.
Profilo nova 2015 U Sollecchia.png
Profilo nova 2015 U Sollecchia.png (10.47 KiB) Viewed 8242 times
Cordialement Umberto

Re: Nova Ophiuchi 2015

Posted: Thu Apr 23, 2015 4:08 pm
by Francois Teyssier
Impressive result at mag 11.5, Christian.
Steve is very interested by the spectroscopic evolution, especially the profile of He I lines.
The ejecta is exceptionnally collimated.
New spectra are required for the next week ; medium and high resolution if possible.
An Atel is considered for next week.

The light curve is not typical, with a slow rise. Looks like the nova begins oscillations three mag under the maximum.
NovaOph2015.PNG
NovaOph2015.PNG (14.86 KiB) Viewed 8220 times
All the best,

François

Re: Nova Ophiuchi 2015

Posted: Fri Apr 24, 2015 5:57 pm
by Joan Guarro Flo
Hi all:

Nova Oph 2015, in the last night.

Regards, J.Guarro