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Re: New transcient, perhaps a nova

PostPosted: Fri Jul 14, 2017 8:42 pm
by Olivier GARDE
Joan Guarro Flo wrote: I will try to observe it with an echelle.
Joan.


Yes, I'm on the nova this night with eshel spectrograph...
Very bright compare to my last spectrum (taken with a LISA) and I see P Cyg profil.

Here's a screen copy of the first exposure.
Image
Exposure of 1200s (I will try to do about 3h exposure)

Re: New transcient, perhaps a nova

PostPosted: Sat Jul 15, 2017 9:10 am
by Olivier GARDE
(first in french, then il english)
La dernière nuit, j’ai pu faire le spectre de la Nova Sct 2017 en haute résolution R=11000 avec 11 poses de 1200s car la cible certe lumineuse pour une nova reste à Mag. 10,9 ce qui est assez peu pour un spectro echelle et un télescope de 400mm de diamètre.

Last night, I was able to do the spectrum of Nova Sct 2017 in high resolution R = 11000 with eshel spectrograph (11 exposures of 1200s each)

Voici donc le spectre « full » on l’on voit toute une série de raies en emission avec un profil P Cyg (sans doute de type IV)
Here's the "full" spectrum, we see a whole series of emission lines with a P Cyg profil (probably type IV)
Image

Et les graphes des raies de Balmer etalonné en vitesse (corrigé de la vitesse heliocentrique qui à cemoment était de 7,1 km/s)
And the graphs of Balmer lines corrected from in heliocentrique velocity of 7.1 km/s)

Image

Image

Image

A partir de ces graphes on peut mesurer la vitesse d’expansion de la Nova et l’on trouve les valeurs suivantes :
- H Alpha : -404,27 km/s (+/- 2,5 km/s)
- B Beta : -331,16 km/s (+/- 3,1 km/s)
- H Gamma : -325,31 km/s (+/- 3,5 km/s)

From these graphs we can measure the expansion velocity of the Nova and we find the following values:
- H Alpha: -404.27 km/s (+/- 2.5 km/s)
- B Beta: -331.16 km/s (+/- 3.1 km/s)
- H Gamma: -325.31 km/s (+/- 3.5 km/s)

A voir dans les prochains jours (si la magnitude de la nova ne diminue pas trop) comment vont évoluer ces vitesses.
To see in the next days (if the magnitude of the nova not decreases too much) how will these velocity evolve.

Re: New transcient, perhaps a nova

PostPosted: Sat Jul 15, 2017 12:55 pm
by Paolo Berardi
Wow, that's great Olivier! The nova brightness is increasing even more. Last AAVSO Vmag is 10.680.
A nova in slow motion...

Paolo

Re: New transcient, perhaps a nova

PostPosted: Sat Jul 15, 2017 5:19 pm
by Christian Buil
Nova Sct 2017 the 14.9 /07 / 2017 by using a Celestron 11 + VHIRES-MO spectrograph (R= 50000). Sum of 8 x 900 sec. exposures:

Image

I confirm an expansion velocity of -404,0 km/s for the date (see also O. Garde evaluation).

By curiosity the spectrum of Be star gamma Cas at the same scale taken the same night (note position of telluric lines):

Image

Christian B

Re: New transcient, perhaps a nova

PostPosted: Sun Jul 16, 2017 5:48 pm
by Christian Buil
A LISA spectrum equipped with a high performance (but low cost) CMOS camera, and also, very narrow slit for max. resolution (here 15 microns wide for R = 2500, uncommon for the LISA spectrograph...)

Technical details are here:

http://www.spectro-aras.com/forum/viewtopic.php?f=8&t=1803&p=8766#p8766

Image

Image

Note the generalized P Cygni profile, fine bleue details and also the clear Na doublet spectral separation (a superior resolution for the LISA).

Christian Buil

Re: New transcient, perhaps a nova

PostPosted: Mon Jul 17, 2017 1:24 pm
by Olivier GARDE
(first in French, then in English)
La dernière nuit, j’ai pu encore faire une série de spectre sur la Nova Sct 2017 toujours aussi lumineuse et accessible avec un spectro eshel
11 spectres de 1200s chacun avec le spectro eshel R=11000
J’ai calculé les nouvelles vitesses en les comparants à celles que j’avais fait le 14 juillet.

Last night I have take some spectra of this Nova, always bright and accessible with an eshel spectrograph.
11 spectra of 1200s each with the eshel R = 11000
I calculated the new velocity by comparing them with those I had take on July 14th.

Voici les résultats :
V Halpha = -372,8 km/s (-404,27 km/s le 14/07) soit une diminution de 31,47 km/s
V Hbeta = - 308,04 km/s (-331,16 km/s le 14/07) soit une diminution de 23,12 km/s
V gamma = -328,42 km/s (-325,31 km/s) la surprise la vitesse a progressé de 3,11 km/s mais comme on est dans la plage d’incertitude de la mesure (+/- 3,5 km/s) faudrait faire d’autres observations pour confirmer ou pas cette évolution.

Here are the results :
V Halpha = -372,8 km / s (-404.27 km / s on 14/07), decrease of 31,47 km / s
V Hbeta = -308,04 km / s (-331.16 km / s on 14/07), decrease of 23,12 km / s
V-gamma = -328,42 km / s (-325.31 km / s) surprise the velocity increased about 3,11 km/s but as it's within the uncertainty range of the measurement (+/- 3,5 km/s) would have to make further observations to confirm or not this evolution.

Quelques graphes:
Some graphs:

1) Comparaison de la raie H Alpha entre le 14 et 16 juillet (évolution en 48h)
1) Comparison of the H Alpha line between July 14th and 16th (evolution in 48h)

Image

2) Les différentes vitesses des raies de Balmer :
2) The different velocity of Balmer lines:

Image

Re: New transcient, perhaps a nova

PostPosted: Mon Jul 17, 2017 4:22 pm
by Joan Guarro Flo
Très bon travail, Olivier !

Congratulations !!

Amicalement, Joan.

Re: New transcient, perhaps a nova

PostPosted: Mon Jul 17, 2017 9:43 pm
by Olivier GARDE
Joan Guarro Flo wrote:Très bon travail, Olivier !

Congratulations !!

Amicalement, Joan.


Merci Joan

As tu essayé de faire cette nova avec ton spectro Lynx ?

Re: New transcient, perhaps a nova

PostPosted: Tue Jul 18, 2017 8:50 am
by Paolo Berardi
Hi all, following the great spectra by Olivier and Christian (very nice also the narrow slit Lisa profile), I show you my last result with Lhires III 1200 (a modest R = 5500). The nova maintains its brightness, yesterday (July 17, 21:00 UT) I measured V mag 10.78.

Image

Compared to my last observation (July 10), a clear change in the H-alpha P-Cyg profile has occurred.

Image

The two minima in the absorption component (two expanding shells?) are already visible in previous spectra (see July 14 profiles by Olivier and Christian) but on 17 the profile has evolved. A detail of P-Cygni absorption:

Image

Si II doublet Rv decreased from 250 Km/s (July 10) to 225 Km/s (July 17).

Image

Paolo

Re: New transcient, perhaps a nova

PostPosted: Tue Jul 18, 2017 1:17 pm
by Olivier GARDE
HI Paolo

Thanks for the spectra.
Ok, the absorption part of H Alpha has clearly changed in one day, I will try this night again...