spectro-aras.com

A recent paper discribe the outburst of CN Cha (Chamaeleon)
which could be a symbiotic nova.
https://iopscience.iop.org/article/10.3 ... 881/aba435
From ~ 2013 to ~ 2018 the object was over mag 10, it is now declining
I do not see any measures of luminosity in the AAVSO database
Unfortunatly the authors have not disclosed their discovery, for instance via an ATel, until this paper ... no comment.

Spectra of the decline are welcome for inclusion in the database
(to be sent to francois mathieu.teyssier at gmail.com and a copy to arasdatabase at gmail.com

I have taken a couple of spectra of this far south object now. It's magnitude has changed significantly over 2 weeks increasing from V=10.1 to V=9.8.
It is in the VSX as a mira although the spectra doesn't look like one now. It changes sometime after 2010. I might keep following it.

Terry

The weather has finally cleared and I managed a few images of CN Cha earlier this week. Here is the spectrum with a few lines marked. There are quite a few others but they don't show up easily given the scaling of the plot.

I agree Terry, its worth keeping an eye on this one

Pete

Terry, Peter,

Excellent results!
Yes, a monitoring should be great. Not easy at the date to define precisely the frequency. It will be easier when we have more spectra.
Photometry also very useful.
Such symbiotic nova event could last years, or decades (see e.g. PU Vul, V1016 Cyg ...)
Lines identification: the commented spectra of RR Tel could help. xls and cvs files can be downloaded from:
http://www.astronomie-amateur.fr/Lines/ ... _SySt.html

Precursor: Nova events in symbiotic stars (including those which harbor a Mira, known as D-Type symbiotics with D = Dust) strongly enhance the recombination continuum which overwhelms the classical TiO bands.

Symbiotic novae:

Thermonuclear explosion phenomenon occurring in the surface layer accumulated on the surface of the white dwarf, as in a classical nova. Symbiotic novae are distinguished from classical novae by the exceptionally long duration (several decades) of the phenomenon. 7 are currently known.

Spectral evolution allows two subgroups to be defined:
- Long phase in which the spectrum resembles that of an A-F super giant;
AG Per, RT Ser, RR Tel, PU Vul
- Nebular phase appearing at maximum brightness after a short or non-existent super-giant phase
V1016 Cyg, V1329 Cyg, HM Sge


Terry: I think that I have not received your spectrum.

Hi Francois
I emailed 2 spectra yesterday. I will resend them if you didn't receive them.
Terry