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The last HR spectrum acquired by Etienne shows a significant change of the red part of H alpha.
It looks like the ejecta are now optically thin.

High and medium resolution spectra of the various lines of interest are welcome to check the stabilisation of the profile of Ha and comparison of the profiles of the various lines : Ha, Hb, Fe II, [OI] 6300, OI 7773 and 8446, Na I D
+ Echelle spectra of course
+ Low res spectra

Hi,

I have some spectra from January 2, 3 and 5 made with a LISA

From bottom to top are 2, 3 and 5 January 2021

Bonjour à tous

Ci dessous le spectre autour de H-Alpha réalisé avec UVEX(4) G1200 le 6/1/2021

spectre complet: Autour H-Alpha:
Pierre

Bonsoir à tous,

Profitant d'un début de soirée clément, je viens de prendre ce soir 9 spectres de 10 minutes sur la Nova Per 2020. La magnitude doit approcher les 12 maintenant.
On retrouve bien cette large raie Halpha avec ses oscillations au sommet. Ce soir, cette oscillation penche du côté du bleu:
Les mouvements d'un soir à l'autre sont particulièrement impressionnants. Et bravo à tous pour ce suivi et ces explications précieuses (tout comme la passionnante conférence de François vendredi dernier )

Bon ciel.

Frederic

Hi all, I've just completed an H-alpha observation with Lhires III and 1200 l/mm grating. Very good sky transparency but strong atmospheric turbulence.



Concurrent differential photometry shows a brightness declining trend with a mean V mag value of ~ 14.02. I used a few dozen of stars in the field with their APASS V mag. There might be an offset. A lot of flux in the optical range is concentrated in the h-alpha emission line (some enters in the filter V band).



Nova image (Mak90, SXV-H9, V filter)



Paolo

I've been trying to understand the evolution of the spectra collected by everyone contributing. I noticed that the profile of H alpha at the very beginning on 26th November is similar to the most recent, that is to say, there appear to be twin peaks. Francois, you commented on the most recent spectrum of H alpha and said that this profile suggested that the ejecta were optically thin. What would explain the appearance on the 26th November, were the ejecta optically thin then?

After this a P Cygni profile developed and the absorption component moved further and further towards the blue. After mid December the profile became a purely emission spectrum.

Can anyone explain to me what is happening?

Hello all,

Here is my new update for the monitoring of the Nova Per 2020.
The following spectra were obtained with an Alpy 600.

The 9th of January at 18 h 17 TU (resolution of 510, JJ = 2459224.2617 and an acquisition time of 60 min) : The 10th of January at 18 h 19 TU (resolution of 508, JJ = 2459225.2635 and an acquisition time of 65 min) : It seems to me that the lines [NII] at 5457A and [OI] at 6364A are now visible in the spectrum... is that correct? The relative intensity of the Halpha line continues to increase and, as the ejecta appears to have become optically thin, the "structure" of the Halpha line is now clearly visible even at low resolution : The increase in the relative intensity of the [OI] line is now clearly visible : Best wishes and clear skies,

Christophe BOUSSIN

Paolo: excellent and very informative result: He I 6678 still missing.
Christophe: l'identification est correcte.

John:
The clues: As I explained during the workshop,
First spectrum 2020-11-26 (Olivier Garde): the bump on the red part of H alpha doesn't appear on H beta profile, thus it -probably- do not belongs to Balmer transition.
At the date, there no identification, no explanation for this feature.
Last echelle spectrum 2020-12-25 (Joan Guarro): the red emission in H alpha line begins to rise. We see it also in H beta, and faintly in H gamma: it belongs to the Balmer series.
No explanation at the date for the development of this red emission component which were observed in other novae.

Thus, the two bump have different origines.

Last: about the absorption systems.
They are still present late December as shown during the workshop.
With maximum absorptions at rv = -1200 and 2100 km/s I have not yet sudied the last data.

Very nice Christophe! The [O I] 6364 line is also included in my last spectra. On January 16th the emission line appears broad, with a prominent blue-shifted peak (very similar to [O I] 6300 line in your last spectrum).



The full profile centered on h-alpha line. I have to change a bit the grating angle to include both lines [O I] 6300 and He I 6678 A (now missing).



François, thanks for the info!

Paolo

Dear Francois, thank you for answering my question about the evolution of H alpha. It’s very helpful.
I didn’t know you did a workshop on this subject. Can I access it?
John.

PS. Found it! Sorry to have missed the presentation but I will watch it on YouTube.