CH Cygni: still surprizing

CH Cygni: still surprizing

Postby Francois Teyssier » Thu May 09, 2019 6:19 pm

After a short flare (recorded also by ARAS spectra) CH Cyg is now at a low luminosity.
CHCyg.PNG
CHCyg.PNG (53.76 KiB) Viewed 186 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
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Re: CH Cygni: still surprizing

Postby Francois Teyssier » Sun May 12, 2019 4:51 pm

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
chcyg_1.png (23.01 KiB) Viewed 145 times


[OIII] region, with He I 5016 and Fe II 5018:
chcyg_2.png
chcyg_2.png (19.52 KiB) Viewed 145 times


H beta in almost pure emission
chcyg_3.png
chcyg_3.png (17.8 KiB) Viewed 145 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
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Re: CH Cygni: still surprizing

Postby Forrest Sims » Wed May 15, 2019 8:48 pm

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
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chcyg_20190515_315_Forrest Sims annotated.png
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Re: CH Cygni: still surprizing

Postby Francois Teyssier » Wed May 15, 2019 11:15 pm

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
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Re: CH Cygni: still surprizing

Postby Francois Teyssier » Thu May 16, 2019 6:10 pm

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

chcyg_20190515_315_Forrest Sims.png


More lines could be identified in the range 5000-5500
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Re: CH Cygni: still surprizing

Postby Christophe Boussin » Fri May 17, 2019 5:49 pm

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 :

_chcyg_20190512_003_Christophe Boussin_3700_7570.png
CH Cyg on May 12th, 2019
_chcyg_20190512_003_Christophe Boussin_3700_7570.png (104.14 KiB) Viewed 45 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.


chcyg_20190512_003_Christophe Boussin_max5.png
CH Cyg on May 12th and 15th, 2019 (comparison)


chcyg_20190512_003_Christophe Boussin_max2.png
CH Cyg on May 12th and 15th, 2019 (comparison, zoom)



Clear skies,

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan) @ ARAS database
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