spectro-aras.com

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) :
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) :

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 : Evolution of FeII lines (27) and (28) between April 18 and 29 : 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 : The relative intensities of HeI lines continue to decrease...

Evolution of the HeI line at 5876A (for example) between April 18 and 29 : The sky has been cloudy for a few days here... we hope other observers have better skies !!

Marion THOMAS et Christophe BOUSSIN

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:

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:
Here is the animation:
Cheers
Hugh

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

Evolution of FeII lines (42) between April 18 and May 5 : Evolution of FeII lines (27) and (28) between April 18 and May 5 : …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 : 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 : The relative intensities of HeI lines continue to decrease...

Evolution of the HeI line at 5876A (for example) : According to the AAVSO website, the magnitude of the Nova is now close to 7 !!
(visual : open circles / Johnson V : green squares) Many more clear skies to all !!

Christophe BOUSSIN

Strong brightening!

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

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) :
Clear skies to all !!

Christophe BOUSSIN

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

The full spectrum from 3840 to 7600 Å



The Balmer's lines velocity



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









Stranges P Cyg profil ???

En complément du spectre obtenu par Olivier,
Nova Cas 2021 ce matin avec le telescope remote SMM-SP
Les raies Fe II (42)
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

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