Nova in Cassiopea (nova Cas 2020)

[Christian Buil]

A high resolution of the nova, August12.9 (presence of cirrus cloud), eShel, R=12000. Halpha



Na D1-D2:



Christian

[etienne bertrand]

Super spectre Christian,

Au niveau du SNR entre Eshel et Lhires, sur Ha par exemple quel est le spectro qui donne le meilleur signal pour temps de pose équivalent ?

[Peter Somogyi]

Yesterdays result, the random absorptions are not noise - perhaps coicidence with ATEL#13941 (CN / C2 bands?), taken spectra at similar time, and the continuum is strange (used only a linear reference star fit). O I 7772 region:

Shooting Ca II IRT region done while sleep (tons of exposures deserved), much less signal than previously, at poor guiding / windy conditions:

No Paschen-end contamination for now, they seem to be fully vanished in 4 days!
Having some wide absorptions (8600-8700A), question is where they are from.
Peter

[Vincent Lecocq]

Hello,

Hereunder a spectrum of the nova taken last night !


clear skies,
Vincent

[Christophe Boussin]

Hello all,

Finally the weather has become good again ... for a while !
I obtained the following spectrum of the nova Cas 2020 the 15th of August at 22 h 48 TU with my Alpy 600 (resolution of 507, JJ = 2459077.4501) and an acquisition time of 75 min :

Nova Cas 2020 on August 15th, 2020

_novacas2020_20200815_950_Christophe Boussin_3750_7565.png (89.63 KiB) Viewed 6962 times

Nova Cas 2020 on August 5th, 6th, 7th and 15th, 2020 (identification of lines from PlotSpectra)

As in the spectrum of Vincent, I note a very strong increase in the relative intensities of the Balmer and Fe II lines, the modification of the shape of the Halpha line and the development of new lines !!

Good luck and clear skies to all for the monitoring of the nova !

Christophe BOUSSIN

[Francois Teyssier]

As in the spectrum of Vincent, I note a very strong increase in the relative intensities of the Balmer and Fe II lines, the modification of the shape of the Halpha line and the development of new lines !!

Yes!
You have also [O I] 6300. This is the [O I] flash: the ejecta is becoming optically thin in the visible range.

Recall: evolution of a classical nova Del 2013: http://www.astrosurf.com/aras/novae/Nova2013Del-2.html with Steve Shore comments

All the best,
François

[Christophe Boussin]

Hello all,

Thank you François for this clarification !!
The evolution of the spectrum over the last few days is really exciting !!

Taking advantage of a new more durable weather window, I obtained the following spectrum last night of the nova Cas 2020 the 17th of August at 22 h 45 TU with my Alpy 600 (resolution of 507, JJ = 2459079.4481) and an acquisition time of 80 min :

Nova Cas 2020 on August 17th, 2020

_novacas2020_20200817_948_Christophe Boussin_3750_7565.png (104.48 KiB) Viewed 6890 times

Nova Cas 2020 on August 5th, 6th, 7th, 15th and 17th, 2020 (identification of lines from PlotSpectra)

Evolution of the Halpha line :

Halpha line on August 5th, 6th, 7th, 15th and 17th, 2020

novacas2020_20200817_948_Christophe Boussin_Halpha.png (24.74 KiB) Viewed 6890 times

The relative intensity and the shape of the Halpha line seems to continue to change but, of course, this requires confirmation at high resolution...


Evolution of the [OI] line :

[OI] line on August 5th, 6th, 7th, 15th and 17th, 2020

novacas2020_20200817_948_Christophe Boussin_OI.png (26.79 KiB) Viewed 6890 times

The relative intensity of the [OI] line seems to have increased since the 15th...to be continued !

Clear skies to all for monitoring the evolution of the nova !!

Christophe BOUSSIN

[Dubreuil Pierre]

Hello

Clear sky last night for the NOVA

UVEX(3) SC8 red6.3 6x900s

_nova2020cas_20200818_847_Pierre Dubreuil @4100@7500.png (13.31 KiB) Viewed 6851 times

Pierre

[Francois Teyssier]

The nova shows oscillations at maximum.

novacas.PNG (5.84 KiB) Viewed 6810 times

The light curve is atypical for a classical , with a very slow rise and now the oscillations.
Daily monitoring at all resolutions is encouraged.

All the best,
François

[Vincent Lecocq]

bonjour,

ci-dessous le spectre de la Nova pris le 19 aout entre 02 h et 03h à l'observatoire Sirene,

bonne journée,

vincent