Alert! Nova Cas 2021 mag 9

Alerts and Monitoring of Novae
Matthieu Le Lain
Posts: 24
Joined: Mon Apr 15, 2019 4:33 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Matthieu Le Lain »

Hello Christophe, all,

Yes i've seen too, but i'm not sure, i said myself than perhaps it's probably only noise ? Which lines did you think particulary ?

Here is a new spectrum with an alpy600 with more exp., to seen a global difference i make a comparison of the two spectra and i tried to identify really distincts lines with this new spectrum.
novacas2021_20210825_963_comp_ml.png
novacas2021_20210901_912_ml.png

Matthieu
Christophe Boussin
Posts: 170
Joined: Sun Aug 21, 2016 6:04 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Christophe Boussin »

Hello all,

Hi Joan,

Thanks for your comment !
The monitoring of the details visible in the Halpha line profile of this nova is really exciting: we need an expert to understand their evolution !
It's also very interesting to see the parallel evolution of the Halpha and HeI 6678 A lines you mention : I look forward to seeing your next echelle spectrum with your remarkable Nou T spectrograph !!


Hi Matthieu,

To try to understand the origin of these details and whether they are noise or not, it seems to me that you could look at the individual 1D spectra that are generated in ISIS (@pro1.fit, @pro2.fit, @pro3.fit, ...) for the final 1D spectrum processing.
Are these details visible on each of them ?

I was thinking, for example, of the FeII lines at 4923, 5018 and 5169 A and, in particular, of the SiII lines at 6347 and 6371 A. The latter seem to be well visible in your spectrum of August 26 !



As usual, I continue the monitoring of the Halpha line of the Nova Cas 2021 and there is, again, some change since August 27 !

So, here is my new comparison between my two last spectra of the Halpha line of Nova Cas 2021 at high resolution on August 31 at 22 h 02 TU (resolution of 19064, JJ = 2459458.4182, 9 x 600s) and on September 2 at 21 h 55 TU (resolution of 18580, JJ = 2459460.4134, 12 x 600s) obtained with my LHIRES III (grating of 2400 lines / mm) and the previous ones in August :
Halpha line of Nova Cas 2021 on August 1st, 8th, 12th, 13th, 21th, 25th, 27th, 31th and on September 2nd 2021
Halpha line of Nova Cas 2021 on August 1st, 8th, 12th, 13th, 21th, 25th, 27th, 31th and on September 2nd 2021
novacas2021_20210902_Halpha_Christophe Boussin.png (60.66 KiB) Viewed 5691 times
Since August 31, a peak located at + 785 km/s emerges on the profile of the Halpha line (it seems to be already visible on the spectrum of August 27).
On the spectrum of September 2, the evolution of the peak is particularly obvious !
Halpha line of Nova Cas 2021 on August 1st, 8th, 12th, 13th, 21th, 25th, 27th, 31th and on September 2nd 2021 (zoom)
Halpha line of Nova Cas 2021 on August 1st, 8th, 12th, 13th, 21th, 25th, 27th, 31th and on September 2nd 2021 (zoom)
novacas2021_20210902_Halpha_zoom_Christophe Boussin.png (82.92 KiB) Viewed 5691 times

(Johnson V : green squares)
Light curve of the Nova CAS 2021 (AAVSO)
Light curve of the Nova CAS 2021 (AAVSO)
Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan + Mewlon 180 F/12 / LHIRES III 2400 / Atik 460EX / Atik 314 L+) @ ARAS database
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Joan Guarro Flo »

Hello,

After some few days of bad weather , I have been able to observe Nova Cas 2021 with SMM teescope.

J.Guarro.
Attachments
novacas2021.png
novacas2021.png (21.65 KiB) Viewed 5674 times
JP Nougayrede
Posts: 152
Joined: Tue Oct 20, 2015 8:33 pm

Re: Alert! Nova Cas 2021 mag 9

Post by JP Nougayrede »

Last night observation, C11 at F7 Alpy 600 CCD 414. Still very bright, Ha line is saturating in less than one minute.
novacas2021_20210906_831_JPN.png
novacas2021_20210906_831_JPN.png (48.33 KiB) Viewed 5611 times

Clear skies,
Jean-Philippe
Christophe Boussin
Posts: 170
Joined: Sun Aug 21, 2016 6:04 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Christophe Boussin »

Hello all,

Hi Jean-Philippe,

Yes, the Nova Cas 2021 is still very bright !
This is a great opportunity to follow it at low and high resolutions !

As I had indicated in my previous post, a peak located at about +785 km/s appeared around August 27 in the profile of the Halpha line of Nova Cas 2021.
So I followed its evolution these last days by taking 2 new high resolution spectra on September 4 at 23 h 22 TU (resolution of 19441, JJ = 2459462.4734, 5 x 600s) and on September 6 at 22 h 00 TU (resolution of 19187, JJ = 2459464.4168, 12 x 600s) with my LHIRES III (grating of 2400 lines / mm).

Here are all the spectra I got between August 27th and September 6th :
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th and 6th 2021
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th and 6th 2021
novacas2021_20210906_Halpha_peak785_Christophe Boussin.png (54.88 KiB) Viewed 5578 times
...and its animation :
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th and 6th 2021 (animation Bass Project)
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th and 6th 2021 (animation Bass Project)
NOVACAS2021_Animation270821_060921.gif (80.16 KiB) Viewed 5578 times
We can clearly note the appearance of this peak around August 27 and its almost total disappearance around September 6....What happened then ?

Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan + Mewlon 180 F/12 / LHIRES III 2400 / Atik 460EX / Atik 314 L+) @ ARAS database
JP Nougayrede
Posts: 152
Joined: Tue Oct 20, 2015 8:33 pm

Re: Alert! Nova Cas 2021 mag 9

Post by JP Nougayrede »

Christophe Boussin wrote:We can clearly note the appearance of this peak around August 27 and its almost total disappearance around September 6....What happened then ?
Hi Christophe. Maybe some kind of inhomogeneity in the fireball ?
Jp
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Joan Guarro Flo »

Hello,

Last night I was observing Nova Cas 2021 and I found that this star was around 6.5 magnitude.

You can see two graphics.

J.Guarro.
Attachments
Nova cas 2021 1.png
Nova cas 2021 1.png (22.41 KiB) Viewed 5520 times
Nova cas 2021 2.png
Nova cas 2021 2.png (19.86 KiB) Viewed 5520 times
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Joan Guarro Flo »

I'm sorry, the first graphic has a mistake, the star is NOVA Cas 2021.

Thanks, J. Guarro.
Christophe Boussin
Posts: 170
Joined: Sun Aug 21, 2016 6:04 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Christophe Boussin »

Hello all,
Jean-Philippe Nougayrede wrote :
Hi Christophe. Maybe some kind of inhomogeneity in the fireball ?
Hi Jean-Philippe,
Yes, why not !
The changes in the profile of the Halpha line are not easy to explain...
The inclination of the system, the complex shape of the ejecta and its expansion, the possible ejection of new material are all parameters to be taken into account by experts in the field. The new maximum of luminosity, which seems to be for soon, is the occasion to follow these changes in the profiles of the lines !
Joan Guarro Flo wrote :
Last night I was observing Nova Cas 2021 and I found that this star was around 6.5 magnitude.
Hi Joan,
Yes, the brightness of the Nova is increasing again and it seems that a new maximum is for very soon !
Light curve of the Nova CAS 2021 (AAVSO)
Light curve of the Nova CAS 2021 (AAVSO)
I obtained a new high resolution spectrum of the Halpha line on September 9 at 21 h 00 TU (resolution of 18373, JJ = 2459467.3754, 7 x 600s) with my LHIRES III (grating of 2400 lines / mm) and, according to the AAVSO, the magnitude of Nova Cas 2021 was about 6.5 at that time !

Here are all the spectra I got between August 27th and September 9th :
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th, 6th and 9th 2021
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th, 6th and 9th 2021
novacas2021_20210909_Halpha_Christophe Boussin.png (54.47 KiB) Viewed 5469 times
The peak around +785 km/s has now completely disappeared and we can note the evolution of the Halpha line profile between September 6 and 9 :
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th, 6th and 9th 2021 (zoom)
Halpha line of Nova Cas 2021 on August 27th, 31th and on September 2nd, 4th, 6th and 9th 2021 (zoom)
novacas2021_20210909_Halpha_peak785_Christophe Boussin.png (61.36 KiB) Viewed 5469 times
Clear skies to all for the next few days !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan + Mewlon 180 F/12 / LHIRES III 2400 / Atik 460EX / Atik 314 L+) @ ARAS database
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: Alert! Nova Cas 2021 mag 9

Post by Joan Guarro Flo »

Hello,

It seems that Nova Cas 2021 wants explain things to us again !

Cheers, J. Guarro.
Attachments
Nova Cas 20211.png
Nova Cas 20211.png (20.41 KiB) Viewed 5429 times
Nova Cas 20212.png
Nova Cas 20212.png (23.13 KiB) Viewed 5429 times
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