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Nova Sgr 2021b - Second nova of the year in Sgr

Posted: Tue Apr 06, 2021 7:17 am
by Francois Teyssier
Please use Nova Sgr 2021b as OBJNAME
François




ATEL #14513 ATEL #14513

Title: Spectroscopic Classification of PNV J17581670-2914490 as a
classical nova
Author: Kenta Taguchi, Miho Kawabata, Masayuki Yamanaka, Keisuke Isogai
(Kyoto University)
Queries: kentagch@kusastro.kyoto-u.ac.jp
Posted: 6 Apr 2021; 05:25 UT
Subjects:Optical, Cataclysmic Variable, Nova, Transient

We report <a href="http://www.kusastro.kyoto-u.ac.jp/~kent ... 8.pdf">our
spectrum</a> of the transient PNV J17581670-2914490.
We obtained the spectrum on 2021-04-05.828 UT using the fiber-fed integral field spectrograph (KOOLS-IFU; <a href="https://ui.adsabs.harvard.edu/abs/2019P ... M/abstract"
target="_blank">Matsubayashi et al. 2019</a>) mounted on the 3.8-m Seimei telescope (<a href="https://ui.adsabs.harvard.edu/abs/2020P ... K/abstract"
target="_blank">Kurita et al. 2020</a>) at Okayama Observatory of Kyoto
University.

As reported to <a href="http://tamkin1.eps.harvard.edu/unconf/f ... 14490.html"
target="_blank">CBAT</a>, this transient was discovered by Andrew Pearce at 8.4 mag (unfiltered) on 2021-04-04.825 UT (see also <a href="http://ooruri.kusastro.kyoto-u.ac.jp/ma ... lert/25655"
target="_blank">vsnet-alert</a> for detail). Rob McNaught reported non-detection on 2021-04-02.776 UT (unfiltered limiting mag 11.0). Seiichiro Kiyota reported multicolor photometry results: B = 9.03, V = 8.02, and Ic = 6.82 (these results were reported at 2021-04-05.4188 UT, but the observation time is not reported). Andrew Pearce also reported multicolor photometry results:
V = 8.08 on 2021-04-05.482 UT, B = 9.16 on 2021-04-05.483 UT, and I = 6.50 on 2021-04-05.484 UT. <a href="https://asas-sn.osu.edu/sky-patrol/coor ... cb7797f26b"
target="_blank">ASAS-SN Sky Patrol</a> also reported photometries: in average, it was g = 14.25 on 2021-04-05.290 UT and g = 14.22 on 2021-04-05.458 UT.

<a href="http://www.kusastro.kyoto-u.ac.jp/~kent ... vj1758.pdf"
target="_blank">Our spectrum</a> shows Balmer lines, Fe II lines, and the Na I D line. Note that the interstellar extinction is not corrected. The Hα line has the P-Cygni profile, whose absorption component is blue-shifted by ∼1000 km/s from the redder emission component (for convenience, we plot the spectrum in two ways: the blue curve is "rest" spectrum in which the emission peak of the Hα line is offset to its rest wavelength to correct the radial velocity of the target. the green one is red-shifted by 1000 km/s from the blue one, for the visibility of absorption components).

Fe II lines have absorption profiles whose wavelengths are consistent with the 1000 km/s blue-shift.
The Na I D line has a combined profile of a "rest" absorption component and a broad absorption component which is blue-shifted by ∼1000 km/s from the "rest" one.
Hidehiko Akazawa also reported <a href="http://akazawa-hide.sakura.ne.jp/keijib ... nSgrSP.png"
target="_blank">his spectrum</a>, confirming our results.

According to our spectrum and the brightness, we conclude that this object is a classical nova. The spectrum is similar to those of the slow nova V1280 Sco in the early stage (<a href="https://ui.adsabs.harvard.edu/abs/2012A ... N/abstract"
target="_blank">Naito et al. 2012</a>, <a href="https://ui.adsabs.harvard.edu/abs/2008A ... K/abstract"
target="_blank">Hanindyo et al. 2008</a>).

Our Spectrum: http://www.kusastro.kyoto-u.ac.jp/~kent ... vj1758.pdf

Re: Nova Sgr 2021b - Second nova of the year in Sgr

Posted: Fri Apr 09, 2021 2:38 pm
by Joan Guarro Flo
Hello,

With not more good conditions I I have observer Nova Sgr 2021b this last morning.

Those are the results, it seems this spectra show an evolution from the first that we can see in the François' message.

Cheers, J.Guarro.

Re: Nova Sgr 2021b - Second nova of the year in Sgr

Posted: Fri Apr 16, 2021 8:32 am
by Paolo Cazzato
Hallo everybody,
here my comparison at low resolution of this Nova taken from 3800A to 7900A. At low resolution I noticed an incrase of the basic lines and a splitting of the h alpha line. I also noticed an incrise of the OI (?) line at the extreme end of the spectrum. Would it be possible an overlap of the Mg line at 7890A in your opinion?

Re: Nova Sgr 2021b - Second nova of the year in Sgr

Posted: Wed Jun 02, 2021 1:40 pm
by Olivier GARDE
The nova spectrum taken from our new 2SPOT setup in Chile taken with an Alpy 600 and RC12 telescope

Image

Re: Nova Sgr 2021b - Second nova of the year in Sgr

Posted: Sun Jul 11, 2021 4:48 pm
by Olivier GARDE
Another spectrum taken yesterday morning from our 2spot setup in Chile

Image

And the evolution with other spectrum taken one month ago

Image