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Re: Probable nova in Hercules mag 6.4 !

PostPosted: Mon Jun 14, 2021 6:59 am
by Stephane Charbonnel
As David Boyd write it, it has completly changed from the day before !

It looks like a nova now but already fainter as 24H before.

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Mon Jun 14, 2021 9:35 am
by Joan Guarro Flo
Hello at all,

As David has said the Nova Her 2021 magnitude has decreased a lot and its aspect has changed.

You can see some graphic comparaisons here.

Cheers, J.Guarro.

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Mon Jun 14, 2021 4:49 pm
by Olivier GARDE
I followed the nova during all the night and was able to see its evolution in 6 hours

The whole spectrum

Image

H Alpha evolution
Image

H Beta evolution
Image

H Gamma evolution
Image

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Tue Jun 15, 2021 10:15 am
by Joan Guarro Flo
Hello,

That is Nova Her2021 this last night, you can see here the good performance of NOU_T echelle with the ASI2600 MM camera.

Cheers, J.Guarro.

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Wed Jun 16, 2021 11:20 am
by Robin Leadbeater
The shift in the H alpha, beta line profiles from blue to red while still centred on the rest wavelength is interesting.
https://britastro.org/specdb/data_graph ... &multi=yes
Increasing transparency might level the line profile but why are we now seeing more emission from the back of the system? Is this an orbital effect ?


Cheers
Robin

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Wed Jun 16, 2021 4:39 pm
by David Boyd
The following plot shows the change in absolute flux of the nova over the last 4 days. These R~1000 spectra have been calibrated in absolute flux using concurrently recorded V magnitudes of 6.35, 8.38 and 9.77 respectively.

David

Nova Her 2021 12-13-15 June.png
Nova Her 2021 12-13-15 June.png (45.38 KiB) Viewed 1276 times

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Wed Jun 16, 2021 9:56 pm
by Daniel Dejean
Modeste contribution lors du test d’une configuration volontairement dégradée d’un Alpy avec une fente de 35microns et une caméra Atik428EX en bin2x2. La résolution obtenue n’est que d’environ 380 mais peut-être intéressante dans certaines situations : raies larges et faible luminosité (ce n’est pas encore le cas ici).
Pour le fun, le graphique a été tracé avec un script Python écrit après les excellentes sessions de Shelyak. Merci encore pour ces formations.

Image

Malgré la faible définition de cette observation il semble possible d'évaluer les vitesses d'expansion de l'ordre de 2600km/s au 15/06. Elle paraît légèrement supérieure en Halpha.

Image

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Thu Jun 17, 2021 11:21 am
by Christophe Boussin
Hello all,

As other observers have noted, the spectrum of Nova Her 2021 is changing very fast !
In particular, the evolution of the Halpha line is already clearly visible at low resolution with a modification of the overall shape of the top of the profile.

I obtained two spectra of the Halpha line of Nova Her 2021 at high resolution on June 14 at 22 h 39 TU (resolution of 18220, JJ = 2459380.4435) and on June 15 at 22 h 43 TU (resolution of 18835, JJ = 2459381.4463) with my LHIRES III (grating of 2400 lines / mm, acquisition time of 60 min for each spectrum (6 x 600s)).

novaher2021_Halpha_Christophe Boussin.png
Halpha line of Nova Her 2021 on June 14th and 15th 2021
novaher2021_Halpha_Christophe Boussin.png (45.77 KiB) Viewed 1228 times

What is most noticeable is the width of the Halpha line but we can also note the evolution in detail of its profile in one day (especially around +1000 km/s) !

Clear skies to all !!

Christophe BOUSSIN

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Thu Jun 17, 2021 2:26 pm
by Paolo Berardi
Hi all, great spectra! My contribution with some observations in near-IR interval, using Lhires III with 830 l/mm NIR blazed grating.

The different evolution of neutral oxygen lines, O I 7772 and O I 8446, from june 13 to June 16 (Lyman-beta pumping?)

Image

I hope to keep observing our interesting subject (but its brightness decreases)...

Clear sky!
Paolo

Re: Probable nova in Hercules mag 6.4 !

PostPosted: Thu Jun 17, 2021 3:06 pm
by Robin Leadbeater
Does anyone have an identification of the strong P Cygni line in early spectra at ~6380 emission/6295 absorption see here for example ?
viewtopic.php?f=36&t=2785#p15737

Thanks
Robin