Alert! Nova Cas 2021 mag 9

Alerts and Monitoring of Novae

Re: Alert! Nova Cas 2021 mag 9

Postby Christian Buil » Fri Apr 09, 2021 11:41 pm

An blue-UV spectrum taken by using UVEX spectrograph on a 200 mm Newton stopped at 125 mm diameter (April 8):

Image

A visible spectral range spectrum captured by using Star'Ex spectrograph and a 200-mm Newton (April 9):

Image

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Nova Cas 2021 Alpy spectrum evening of 2021 Apr 11

Postby HughAllen » Tue Apr 13, 2021 7:41 am

Here is my latest Alpy spectrum of Nova Cas 2021 at 23deg above my northern horizon. Continued Balmer and HeI emission all with strong P Cygni profiles, such a stable nova!

Nova Cas 2021 on 2021 Apr 11 21.10UT.png
Nova Cas 2021 on 2021 Apr 11 21.10UT.png (25.77 KiB) Viewed 1152 times
Hugh Allen
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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Thu Apr 15, 2021 10:44 am

Hello all,

Nice spectrum Hugh because the nova cannot be caught so easily above the horizon in the early evening !
For me, the nova now becomes observable in better conditions in the second part of the night and so, the following spectrum was obtained the 14th of April at 1 h 38 TU (resolution of 525, JJ = 2459318.568) with my Alpy 600 and an acquisition time of 45 min (15 x 180s) :

_novacas2021_20210414_068_Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 14th, 2021
_novacas2021_20210414_068_Christophe Boussin_3600_7395.png (85.16 KiB) Viewed 1102 times


novacas2021_20210414_068_Christophe Boussin_zoom.png
Nova Cas 2021 on April 14th, 2021 (zoom)

The Si II lines at 5958 (?), 5979 (?), 6347 and 6371A are still clearly visible.

Evolution of the Nova Cas 2021 from March 20 to April 14 :
novacas2021_20210414_068_Christophe Boussin.png
Nova Cas 2021 on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th and 14th 2021 (identification of some lines from PlotSpectra)

The general appearance of the spectrum remains steadly the same over the days.

Evolution of the Halpha line :
novacas2021_20210414_068_Christophe Boussin_Halpha_vitesse.png
Halpha line on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th and 14th 2021
novacas2021_20210414_068_Christophe Boussin_Halpha_vitesse.png (46.26 KiB) Viewed 1102 times


novacas2021_20210414_068_Christophe Boussin_Halpha_vitesse_zoom.png
Halpha line on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th and 14th 2021 (zoom)
novacas2021_20210414_068_Christophe Boussin_Halpha_vitesse_zoom.png (53.36 KiB) Viewed 1102 times

Since April 4, the P Cyg profile of the Halpha line shows little changes at low resolution.

Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Sun Apr 18, 2021 5:56 pm

Hello all,

Here is my update for the monitoring of the Nova Cas 2021 with two new spectra.
The first one was obtained the 16th of April at 0 h 58 TU (resolution of 512, JJ = 2459320.5402) with my Alpy 600 and an acquisition time of 60 min (12 x 300s) :

_novacas2021_20210416_040_Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 16th, 2021
_novacas2021_20210416_040_Christophe Boussin_3600_7395.png (84.07 KiB) Viewed 1030 times

and the second one was obtained the 18th of April at 1 h 33 TU (resolution of 522, JJ = 2459322.5645) with my Alpy 600 and an acquisition time of 40 min (20 x 120s) :

_novacas2021_20210418_065_Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 18th, 2021
_novacas2021_20210418_065_Christophe Boussin_3600_7395.png (98.89 KiB) Viewed 1030 times

novacas2021_20210418_065_Christophe Boussin_zoom.png
Nova Cas 2021 on April 18th, 2021 (zoom)


Evolution of the Nova Cas 2021 from March 20 to April 18 :
novacas2021_20210418_065_Christophe Boussin.png
Nova Cas 2021 on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th, 14th, 16th and 18th 2021 (identification of some lines from PlotSpectra)


Evolution of the Halpha line :
novacas2021(normcont)_20210418_065_Christophe Boussin_Halpha_vitesse.png
Halpha line on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th, 14th, 16th and 18th 2021
novacas2021(normcont)_20210418_065_Christophe Boussin_Halpha_vitesse.png (45.09 KiB) Viewed 1030 times

novacas2021(normcont)_20210418_065_Christophe Boussin_Halpha_vitesse_zoom.png
Halpha line on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th, 14th, 16th and 18th 2021 (zoom)
novacas2021(normcont)_20210418_065_Christophe Boussin_Halpha_vitesse_zoom.png (57.62 KiB) Viewed 1030 times


I note a decrease in the relative intensity of the HeI lines as well as a displacement of the "blue" part of the P Cyg profile (here on the HeI line at 5876A).
novacas2021(normcont)_20210418_065_Christophe Boussin_HeI_5876.png
HeI line at 5876A on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th, 14th, 16th and 18th 2021
novacas2021(normcont)_20210418_065_Christophe Boussin_HeI_5876.png (57.25 KiB) Viewed 1030 times


Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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Re: Alert! Nova Cas 2021 mag 9

Postby Christian Buil » Mon Apr 19, 2021 5:34 pm

A Star'Ex spectrum taken the April 19.122 (I use here a 200 mm Newton stopped to 125 mm diameter and an experimental Star'Ex version (use special optical glass):

Image

A high contrast version:

Image

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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Thu Apr 22, 2021 11:23 am

Hello all,

Here is my last spectrum of the Nova Cas 2021 obtained the 21th of April at 0 h 42 TU (resolution of 518, JJ = 2459325.5292) with my Alpy 600 and an acquisition time of 60 min (20 x 180s) :

_novacas2021_20210421_029_Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 21th, 2021
_novacas2021_20210421_029_Christophe Boussin_3600_7395.png (101.15 KiB) Viewed 885 times

novacas2021_20210421_029_Christophe Boussin_zoom_2D.jpg
Nova Cas 2021 on April 21th, 2021 (zoom)

The FeII line at 5169 A is clearly visible in the spectrum of the Nova Cas 2021 and the Fe II lines at 4923 and 5018 A are blended with the helium lines.

Evolution of the Nova Cas 2021 from March 20 to April 21 :
novacas2021_20210421_029_Christophe Boussin.png
Nova Cas 2021 on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th, 14th, 16th, 18th and 21th 2021 (identification of some lines from PlotSpectra)


Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Fri Apr 23, 2021 5:27 pm

Hello all,

Here is our last spectrum of the Nova Cas 2021 obtained the 23th of April at 2 h 05 TU (resolution of 517, JJ = 2459327.5868) with an Alpy 600 and an acquisition time of 60 min (30 x 120s) :

_novacas2021_20210423_087_Marion Thomas and Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 23th, 2021
_novacas2021_20210423_087_Marion Thomas and Christophe Boussin_3600_7395.png (91.79 KiB) Viewed 823 times

novacas2021_20210423_087_Marion Thomas and Christophe Boussin_zoom.png
Nova Cas 2021 on April 23th, 2021 (zoom)


Back to...the past, the Fe II line (42) at 5169A is visible from April 16 in our spectra...
The FeII lines (42) at 4923, 5018 and 5169 A have remained broadly unchanged since our last spectrum on April 21.
novacas2021(normcont)_20210423_087_Marion Thomas and Christophe Boussin_FeII_zoom.png
Fe II (42) and (49 ?) lines on April 4th, 14th, 16th, 18th, 21th and 23th 2021(zoom)

Could Fe II (49) lines be visible in our latest spectra ?

Evolution of the Nova Cas 2021 from March 20 to April 21 :
novacas2021_20210423_087_Marion Thomas and Christophe Boussin.png
Nova Cas 2021 on March 20th, 23th, 24th, 29th, 30th, 31th and on April 1st, 2nd, 3rd, 4th, 14th, 16th, 18th, 21th and 23th 2021 (identification of some lines from PlotSpectra)


Clear skies to all !!

Marion THOMAS and Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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Re: Alert! Nova Cas 2021 mag 9

Postby Christian Buil » Sat Apr 24, 2021 12:42 am

Star'Ex spectrum the April 24.1, 2021:

Image

Image

(8-inch Newton f/5 telescope stopped at f/8 -> 3750-7100 A valuable spectral range).

Christian Buil
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Re: Alert! Nova Cas 2021 mag 9

Postby Francois Teyssier » Mon Apr 26, 2021 1:07 pm

ATel:

ATEL #14577 ATEL #14577

Title: V1405 Cas (= PNV J23244760+6111140) now displaying Fe II emission
Author: S. N. Shore (Univ. of Pisa), C. Buil, P. Dubovsky, P. Berardi,
M. Bajer, C. Boussin, J. Guarrò, F. Teyssier, E. Bertrand, J. M.
Viannet, D. Boyd, F. Boubault, H. Allen, M. Le Lain, P. le Dû, P.
Cazzato, J. Coffin, K. Shank, E. Bressinck, O. Garde, K. Gurney, R.
Leadbeater (ARAS Group)
Queries: steven.neil.shore@unipi.it
Posted: 26 Apr 2021; 12:56 UT
Subjects:Optical, Nova, Transient

We report that the slow nova Cas 2021 (V1405 Cas = PNV J23244760+6111140), discovered in outburst on 2021 Mar 18.4 (CBET #4945, ATel #14471, #14472, #14476, #14478, #14482, #14530) has begun to display Fe II absorption features.
The nova has been continually monitored by ARAS observers with a variety of telescopes (ranging from 20 to 28 cm and with spectrographs ranging in resolution from about
518 to 9500 covering the optical interval from about 3400 - 7600 A since
2021 Mar. 19.7UT with an accumulated archive to date of over 90 spectra (all spectra and observational details are available from the ARAS archive
website).

The last spectrum to show no evidence for any Fe II absorption was obtained on 2021 Apr. 03.7UT; a very narrow emission at Fe II 5169 (FWZI ~ 100 km/s, vrad ~ 0 km/s) was present but the upper limit to any absorption at vrad>
-2000 km/s was EW < 0.010 A) while on 2021 Apr. 6.7UT a strong, detached absorption was present (0.5 A) with a minimum at -1200 km/s (FWZI ~ 500 km/s), confirmed on Apr. 7.7UT). The absorption was both stronger (2.3
A) and broader (FWZI ~ 2000 km/s) on Apr 19.2UT; most strong optical of Fe II permitted showed similar profiles. In contrast, during the last observation, Si II 6347 showed very weak absorption and both Si II components continued to show the same narrow emission at vrad ~ 0 km/s as the Fe II lines. The P Cyg-like profiles on He I 4471, 5876, 6678, and 7065A showed the absorption component maximum radial absorption velocities of -1600 km/s contiguous with a broad emission component that extended to +1600 km/s (there was also enhanced emission at vrad ~ 0 km/s on these lines).

Although absent on Apr. 14.8UT, Ca II K appeared in absorption on Apr.19.7 (vrad = -900 km/s, EW = 1.5A, no emission) and, aside from the Balmer, He I, Fe II, and Si II lines, the only other feature is a complex emission centered at around 6244 A (Fe II and Al II).

The hydrogen series showed a systematic development. Although an absorption component on Halpha extending to -2500 km/s had been detected in the earlier spectra on Mar. 22UT, that had disappeared by Apr. 3 to be replaced by emission extending to the same velocity and a strong absorption core at about the same velocity as the He I and metal ion transitions, -1600 km/s; the blueward emission had vanished by Apr.22; the maximum emission velocity remains about -2000 km/s. The Balmer series in the last spectra, Apr.
19, showed a progression in the radial velocity of the absorption minimum from -1200 km/s at Halpha to -1000 km/s at Hdelta but with the same maximum velocities of -1600 km/s
(absorption) and +2000 km/s (emission).

Observations are continuing and will be available through the URL linked below.

------------------------------------------------------------------------------
Password Certification: S. N. Shore (shore@df.unipi.it)
https://www.astronomerstelegram.org/?read=14577
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Re: Alert! Nova Cas 2021 mag 9

Postby Christophe Boussin » Tue Apr 27, 2021 6:49 pm

Hello all,

Here is my last spectrum of the Nova Cas 2021 obtained the 27th of April at 1 h 10 TU (resolution of 534, JJ = 2459331.5488) with an Alpy 600 and an acquisition time of 60 min (30 x 120s) :

_novacas2021_20210427_049_Christophe Boussin_3600_7395.png
Nova Cas 2021 on April 27th, 2021
_novacas2021_20210427_049_Christophe Boussin_3600_7395.png (98.25 KiB) Viewed 570 times


novacas2021_20210427_049_Christophe Boussin_zoom.png
Nova Cas 2021 on April 27th, 2021 (zoom)


The relative intensities of the FeII lines have clearly increased since April 25 !

Evolution of FeII lines (42) between April 18 and 27 :
novacas2021(normcont)_20210427_049_Christophe Boussin_FeII_zoom42.png
Fe II (42) lines on April 18th, 21th, 23th, 23th,24th, 25th and 27th 2021(zoom)


Evolution of FeII lines (27) and (28) between April 18 and 27 :
novacas2021(normcont)_20210427_049_Christophe Boussin_FeII_zoom27_28.png
Fe II (27) and (28) lines on April 18th, 21th, 23th, 23th,24th, 25th and 27th 2021(zoom)


At the same time, the relative intensities of the HeI lines have significantly decreased !

Evolution of the HeI line at 5876A (for example) :
novacas2021(normcont)_20210427_049_Christophe Boussin_HeI_5876.png
He I line at 5876A on April 18th, 21th, 23th, 23th,24th, 25th and 27th 2021(zoom)



Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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Posts: 109
Joined: Sun Aug 21, 2016 6:04 pm

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