Alert! Nova Cas 2021 mag 9

Alerts and Monitoring of Novae

Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Sat May 01, 2021 9:47 pm

Hello all,

Here is our last update for the monitoring of the Nova Cas 2021 with two new spectra.
The first one was obtained the 28th of April at 1 h 49 TU (resolution of 525, JJ = 2459332.5756) with an Alpy 600 and an acquisition time of 60 min (40 x 90s) :

_novacas2021_20210428_076_Marion Thomas et Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 28th, 2021
_novacas2021_20210428_076_Marion Thomas et Christophe Boussin_3600_7395.png (90.01 KiB) Viewed 1599 times


and the second one was obtained the 29th of April at 1 h 19 TU (resolution of 539, JJ = 2459333.5548) with an Alpy 600 and an acquisition time of 30 min (20 x 90s) :

_novacas2021_20210429_055_Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 29th, 2021
_novacas2021_20210429_055_Christophe Boussin_3600_7395.png (103.18 KiB) Viewed 1599 times


novacas2021_20210429_055_Christophe Boussin.png
Nova Cas 2021 on April 29th, 2021 (zoom)



The relative intensities of the FeII lines continue to increase but it seems less rapidly between the 27th and the 29th than between the 25th and the 27th...

Evolution of FeII lines (42) between April 18 and 29 :
novacas2021(normcont)_20210429_055_Christophe Boussin_FeII_zoom42.png
Fe II (42) lines on April 18th, 21th, 23th,24th, 25th, 27th, 28 and 29th 2021(zoom)


Evolution of FeII lines (27) and (28) between April 18 and 29 :
novacas2021(normcont)_20210429_055_Christophe Boussin_FeII_zoom27_28.png
Fe II (27) and (28) lines on April 18th, 21th, 23th,24th, 25th, 27th, 28 and 29th 2021(zoom)


Note also the evolution of the “blue” part of the Balmer lines from Halpha to Hdelta visible even at low resolution.

Evolution of the “blue” part of the Halpha line at low resolution (for example) between April 18 and 29 :
novacas2021(normcont)_20210429_055_Christophe Boussin_Halpha.png
Halpha line on April 18th, 21th, 23th, 24th, 25th, 27th, 28 and 29th 2021(zoom)


The relative intensities of HeI lines continue to decrease...

Evolution of the HeI line at 5876A (for example) between April 18 and 29 :
novacas2021(normcont)_20210418_065_Christophe Boussin_HeI_5876.png
He I line at 5876A on April 18th, 21th, 23th, 24th, 25th, 27th, 28 and 29th 2021(zoom)


The sky has been cloudy for a few days here... we hope other observers have better skies !!

Marion THOMAS et 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
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Re: Alert! Nova Cas 2021 mag 9

Postby HughAllen » Mon May 03, 2021 12:24 am

Alpy 600 spectrum from this evening 2021.05.02. The FeII lines continue to strengthen and the P Cygni profile on the H alpha emission has now disappeared at the Alpy resolution:

NovaCas2021_020521.png
NovaCas2021_020521.png (30.1 KiB) Viewed 1561 times
Hugh Allen
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Re: Alert! Nova Cas 2021 mag 9

Postby HughAllen » Wed May 05, 2021 9:44 pm

Inspired by Christophe's wonderful composites, I created an animation of the Alpy 600 spectra that I have captured up until May 2. The spectra have been flux calibrated using the Vmag data from the AAVSO database:

Nova Cas 2021 Vmag evolution to 2021 May 2 from AAVSO database.png
Nova Cas 2021 Vmag evolution to 2021 May 2 from AAVSO database.png (31.29 KiB) Viewed 1505 times


Here is the animation:

novacas2021_20210322-20210502.gif
novacas2021_20210322-20210502.gif (257.65 KiB) Viewed 1505 times


Cheers
Hugh
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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Thu May 06, 2021 10:23 pm

Hello all,

Thank you Hugh !
You did a great job with the animation of your spectra, very interesting and very educational which shows so well the evolution of the Balmer, He I and Fe II lines !!

Here is my last update for the monitoring of the Nova Cas 2021.
The following spectrum was obtained the 5th of May at 0 h 41 TU (resolution of 541, JJ = 2459339.5283) with an Alpy 600 and an acquisition time of 60 min (40 x 90s) :

_novacas2021_20210505_028_Christophe Boussin_3600_7395.png
Nova Cas 2021 on May 5th, 2021
_novacas2021_20210505_028_Christophe Boussin_3600_7395.png (96.85 KiB) Viewed 1471 times

novacas2021_20210505_028_Christophe Boussin.png
Nova Cas 2021 on May 5th, 2021 (zoom)


The relative intensities of the FeII lines continue to increase...

Evolution of FeII lines (42) between April 18 and May 5 :
novacas2021(normcont)_20210505_028_Christophe Boussin_FeII_zoom42.png
Fe II (42) lines on April 18th, 21th, 23th,24th, 25th, 27th, 28th, 29 th and May 5th 2021(zoom)


Evolution of FeII lines (27) and (28) between April 18 and May 5 :
novacas2021(normcont)_20210505_028_Christophe Boussin_FeII_zoom27_28.png
Fe II (27) and (28) lines on April 18th, 21th, 23th,24th, 25th, 27th, 28th, 29 th and May 5th 2021(zoom)


…and some Fe II multiplets are starting to be more obvious: Fe II (74) for example !

Evolution of FeII lines (74) between April 18 and May 5 :
novacas2021(normcont)_20210505_028_Christophe Boussin_FeII_zoom74.png
Fe II (74) lines on April 18th, 21th, 23th,24th, 25th, 27th, 28th, 29 th and May 5th 2021(zoom)


The evolution of Balmer lines continues as we can see on this enlargement of the Halpha line at low resolution between April 18 and May 5 :
novacas2021(normcont)_20210418_065_Christophe Boussin_Halpha.png
Halpha line on April 18th, 21th, 23th,24th, 25th, 27th, 28th, 29 th and May 5th 2021(zoom)


The relative intensities of HeI lines continue to decrease...

Evolution of the HeI line at 5876A (for example) :
novacas2021(normcont)_20210418_065_Christophe Boussin_HeI_5876.png
He I line at 5876A on April 18th, 21th, 23th,24th, 25th, 27th, 28th, 29 th and May 5th 2021(zoom)


According to the AAVSO website, the magnitude of the Nova is now close to 7 !!
(visual : open circles / Johnson V : green squares)
Light_Curve_NOVACAS2021.JPG
Light curve of the Nova CAS 2021 (AAVSO)


Many more 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
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Alert! Nova Cas 2021 mag 6 !!!

Postby Francois Teyssier » Sat May 08, 2021 9:18 am

Strong brightening!

NovaCas2021.png
NovaCas2021.png (22.23 KiB) Viewed 1406 times
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Re: Alert! Nova Cas 2021 mag 9

Postby Olivier GARDE » Sun May 09, 2021 1:14 am

Yes very strong brightening and easy target with an eshel spectrograph.

Image
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Sun May 09, 2021 3:31 am

Hello all,

There are a lot of changes in Balmer's lines !!
Here is my last update for the monitoring of the Nova Cas 2021.
The following spectrum was obtained the 9th of May at 1 h 10 TU (resolution of 542, JJ = 2459343.5488) with my Alpy 600 and an acquisition time of 30 min (20 x 90s) :

_novacas2021_20210509_049_Christophe Boussin_3600_7395.png
Nova Cas 2021 on May 9th, 2021
_novacas2021_20210509_049_Christophe Boussin_3600_7395.png (101.77 KiB) Viewed 1347 times

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
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Re: Alert! Nova Cas 2021 mag 9

Postby Olivier GARDE » Sun May 09, 2021 3:08 pm

A spectrum taken this morning with an eShel spectrograph (R=11000)

The full spectrum from 3840 to 7600 Å

Image

The Balmer's lines velocity

Image

And others parts of the spectrum still on Balmer's lines

Image

Image

Image

Image

Stranges P Cyg profil ???
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
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Re: Alert! Nova Cas 2021 mag 9

Postby Francois Teyssier » Sun May 09, 2021 5:44 pm

En complément du spectre obtenu par Olivier,
Nova Cas 2021 ce matin avec le telescope remote SMM-SP

NovaCas2021_2021-05-09.png


Les raies Fe II (42)

asdb_NovaCas2021_20210509_102_Fe II 4924 Fe II 5018 Fe II 5169.png
asdb_NovaCas2021_20210509_102_Fe II 4924 Fe II 5018 Fe II 5169.png (18.63 KiB) Viewed 1278 times


Deux systémes d'absorption clairement visibles avec un maximum d'absorption observé à -180 et -650 km/s respectivement, et une velocité maximale de l'absorption à -1000 km/s

Vu la luminosité et le caractére trés particulier de cette nova (really very pretty bad nova!) un suivi quotidien est souhaitable.

François
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Nova Cas 2021 now around mag 5.3!

Postby HughAllen » Tue May 11, 2021 10:15 pm

My Alpy spectrum from yesterday evening. I think the CaII pair in the violet is particularly striking. Really a wonderful nova to observe.

Nova Cas 2021 2021.05.10.png
Nova Cas 2021 2021.05.10.png (50.78 KiB) Viewed 1156 times
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