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CH Cygni: still surprizing
Posted: Thu May 09, 2019 6:19 pm
by Francois Teyssier
After a short flare (recorded also by ARAS spectra) CH Cyg is now at a low luminosity.
- CHCyg.PNG (53.76 KiB) Viewed 7575 times
Message from Margarita Karovska:
CH Cyg seems to be doing a very interesting things (at least photometrically).
When will be able to continue with the observations?
Spectroscopic monitoring at high cadency is strongly recommended. CH Cyg is now an easy target during mid-night
François
Re: CH Cygni: still surprizing
Posted: Sun May 12, 2019 4:51 pm
by Francois Teyssier
Very low luminosity V ~ 8.6
Impressive changes in a few days.
Na I D emission lines are increasing (very low ionization level)
- chcyg_1.png (23.01 KiB) Viewed 7534 times
[OIII] region, with He I 5016 and Fe II 5018:
- chcyg_2.png (19.52 KiB) Viewed 7534 times
H beta in almost pure emission
- chcyg_3.png (17.8 KiB) Viewed 7534 times
Comments from Margarita Karovska:
the interesting thing is that CH Cyg (V and B) its getting fainter (abruptly) and in a relatively short time period; When this happened in the past, it indicated a jet ejection and dimming of the LC by the ejecta/dust in the inner circumbinary environment. So close spectral and photometric monitoring in the next few months would be of a great interest.
Monitoring of the event at high cadency is strongly recommended
François
Re: CH Cygni: still surprizing
Posted: Wed May 15, 2019 8:48 pm
by Forrest Sims
Here is my low resolution contribution on CH Cyg from last night using the Shelyak LISA. I have exaggerated the vertical scale. I have attempted to identify the Oxygen, Fe and Nitrogen lines. Do these look correct?
Woody
Re: CH Cygni: still surprizing
Posted: Wed May 15, 2019 11:15 pm
by Francois Teyssier
Hi Woody,
Correct, unless high ionization Fe lines.
CH Cyg is a peculiar symbiotic, powered by accretion and temperature of the hot component ~ 50 000 K (only!).
Most of the lines are low ionized lines (allowed and forbidden) such as Fe, Ti, ...
Cheers,
François
Re: CH Cygni: still surprizing
Posted: Thu May 16, 2019 6:10 pm
by Francois Teyssier
Hi Woody,
Here's an identification on your spectrum
I used your spectrum of RX Lep to detect the lines which appears at that resolution
More lines could be identified in the range 5000-5500
Re: CH Cygni: still surprizing
Posted: Fri May 17, 2019 5:49 pm
by Christophe Boussin
Hello all,
Here is my contribution to the monitoring of CH Cyg.
I obtained the following spectrum the 12th of May at 00 h 03 TU with my Alpy 600 (resolution of 503, JJ = 2458615.5027) and an acquisition time of 27 min :
- CH Cyg on May 12th, 2019
- _chcyg_20190512_003_Christophe Boussin_3700_7570.png (104.14 KiB) Viewed 7434 times
Just to highlight the effect of the resolution on the detection of spectral lines, here is a comparison of the Forrest Sims spectrum (LISA) of CH Cyg with mine (Alpy).
I indicated the position of the same lines identified by François.
- CH Cyg on May 12th and 15th, 2019 (comparison)
- CH Cyg on May 12th and 15th, 2019 (comparison, zoom)
Clear skies,
Christophe BOUSSIN
Re: CH Cygni: still surprizing
Posted: Sun Jun 16, 2019 1:22 pm
by Christian Buil
The blue part of CH Cyg spectrum the 15.99/06/2019 at moderate reslolution (UVEX 1200 l/mm) :
Possible significant evolution is I compare to a 16/03/05/2109 spectrum (but a low resolution spectrum, comparison is not easy) :
A tentative for adjust resolution (with caution) :
Christian Buil