Alert! Nova Cas 2021 mag 9

[Joan Guarro Flo]

Hello at all,

That is Nova Cas 2021 on the night 30 12 2021.

Have a nice New Year, J. Guarro.

[etienne bertrand]

https://www.astrogeo.va.it/ans_spectros ... index.html

[HughAllen]

Thanks Etienne for a very interesting link to ATel 15093. From the series of spectra that I have been capturing with my Alpy spectroscope I could see that the pair of emission lines, NIII 4638Å (Bowen blend with CIII) and He II 4686Å, made a first appearance in early August coincident with the nova fading to around mag 8.5, before disappearing as the nova re-brightened. The nebula line [N II] 5755Å also made a brief appearance:

Nova_Cas_2021_2021.07.20-2021.09.06_HughAllen.png (66.12 KiB) Viewed 16417 times

The spectrum of this beautiful nova has been oscillating as much as its brightness!

Cheers
Hugh

[Joan Guarro Flo]

Hello,

This is Nova Cas 2021 on first 2022 days.

Cheers, J. Guarro.

[Joan Guarro Flo]

Hello,

That is another example of its movements.

Cheers, J. Guarro.

[Joan Guarro Flo]

Hello,

This last January I have been observing Nova Cas 2021, almost every day from Piera and SMM observatories. The star has been changing its graphic overall on the blue region.

That picture shows its current state.

Regards, J. Guarro.

[HughAllen]

I recently brought together the 46 spectra that I captured 2021 March 22 - 2022 March 22 to paint a spectroscopic portrait of Nova Cas 2021. The results are described in a short paper in the Variable Star Section Circular no.192 just published by the British Astronomical Association, which can be downloaded as a pdf at https://britastro.org/vss/VSSC192.pdf
Here is a superposition of the spectra that is one of the figures from the paper:

Figure 4 Compilation of Nova Cas 2021 spectra.png (337.68 KiB) Viewed 14335 times

This nova has been a hugely enjoyable spectroscopic project
Cheers
Hugh

[Christophe Boussin]

Hi Hugh,

You did a really great job !!
Yes, this nova was really amazing to follow and... the story is not quite over !

I'm back with a new spectrum of the Nova Cas 2021 obtained the 19th of June at 0 h 40 TU (resolution of 542, JJ = 2459749.528) with my Alpy 600 and an acquisition time of 50 min (5 x 600s) :

Nova Cas 2021 on June 19th, 2022

_novacas2021_20220619_028_Christophe Boussin_3700_7396.png (95.42 KiB) Viewed 14035 times

Nova Cas 2021 on June 19th, 2022 (probable identification of some lines from PlotSpectra)

As you indicate in your paper, I also wonder if the line at 5303 A is indeed that of [Fe XIV] ?

(Johnson V : green squares)

Light curve of the Nova CAS 2021 (AAVSO)

According to the AAVSO website, the magnitude of the Nova is now close to 11 !!

Clear skies to all !!

Christophe BOUSSIN

[Christophe Boussin]

Hi all,

With delay, here is a new spectrum of the Nova Cas 2021 obtained the 17th of September at 23 h 07 TU (resolution of 529, JJ = 2459840.4633) with my Alpy 600 and an acquisition time of 40 min (4 x 600s) :

Nova Cas 2021 on September 17th, 2022

_novacas2021_20220917_963_Christophe Boussin_3700_7396.png (74.91 KiB) Viewed 12780 times

Nova Cas 2021 on September 17th, July 29th and June 19th, 2022 (identification of some lines from PlotSpectra)

I note a very clear evolution of the [Fe VII] lines at 5721 and 6087 A !

(Johnson V : green squares)

Light curve of the Nova CAS 2021 (AAVSO)

According to the AAVSO website, the magnitude of the Nova is still below 12 : it's still an easy target but unfortunately for me, the weather looks like a parade of clouds !!
Will anyone have better luck?

Clear skies to all !!

Christophe BOUSSIN