AAVSO Alert Notice 454: Monitoring of CH Cyg requested

[Francois Teyssier]

Hi Robin and Thierry
Very nice spectra and interesting campaign
Low res spectra in 2011 : http://www.astronomie-amateur.fr/feuill ... 20Cyg.html
Note the impressive lines evolution
I come back tomorrow from holidays

Best regards

François

[Robin Leadbeater]

Hi François,

Welcome to the campaign. I was beginning to wonder why you had not joined in with your favourite subject I hope you can take some more CH Cyg spectra next week. I am away for a few days so I will not be able to take any more spectra until Monday or Tuesday at the earliest.

Best Wishes
Robin

[Thierry Garrel]

Maximun time coverage of CH cyg at my location is 5H after 00H20 TU, beginning at 20° above the horizon, finishing at 70° 1H before sunset. I've done 5 eshell spectra of 1H each yesterday without noticed any flickering. I asked to Margarita for observation cadence needed.
Well, i slept comfortably and let the telescope in automatic mode in the frozen night. It will be possible to do this every nights depending of the weather.
Joined are the fit spectra for whom want to chek filly lamp calibration method.

T

[Christian Buil]

Hi all,

On the attached portion of eShel spectrum (C11 telescope) the arrow indicate a spectral region apprently in emission in the published Thierry spectrum
(my spectrum is taken last night - 10/03/2012).

I hope to open quickly an ARAS page for compile CH Cyg data (a base also for your proper analysis).

Christian Buil

[Francois Teyssier]

Hi all,
I hope to realize a LISA spectrum tomorrow morning.
But the lines became weak. I'm not sure the result will be very interesting.
At such a luminosity, eShel is the adequate spectrograph.

Here's the historic light curve from AAVSO database. Semi-regular pusating variable up to the first 1963 outburst.



The last year curve : note the giant pulsation whose approximate period is 100 d. Always increasing luminosity. I hope that ALL the eShel equiped amateurs will join the campaign.
I think that the campaign should be continue.



Here's a resolved image of the peculiar star :




About identification :
- 5018.5 line on Robin spectrum must be FeII rather than He I
- The "spectral region apprently in emission" could be an enhnacment of the continuum produced by the activity of the hot star.
It shoud be interesting to compare this region with da M6 or M7 normal giant star.

"We observed the symbiotic star CH Cyg with the 70 cm telescope of the Crimean Astrophysical Observatory in 1982, during its active phase, when it was brighter than 6m in the V band. We simultaneously detected the continuum brightness at wavelengths of 3737, 5092, and 5500 Å with a time resolution of 20 s"

Astronomy Reports,Volume 50, Number 1, 43-54, DOI: 10.1134/S1063772906010057
Nonradial pulsations of the hot component of the symbiotic star CH Cyg during its active phase
N. I. Bondar’ and V. V. Prokof’eva
But the publication isn't accessible for free

I began to udate my page http://www.astronomie-amateur.fr/feuill ... 20Cyg.htmlwith
-lines indentification (to complete)
- and various references.
For line identification (numerous FeII and [FeII] lines) see especially : http://cdsbib.u-strasbg.fr/cgi-bin/cdsb ... ..72..391H
Astron. Astrophys., Suppl. Ser., 72, 391-413 (1988)
Line spectrum variations during the CH Cygni outburst of 1977-1986.
HACK M., ENGIN S., RUSCONI L., SEDMAK G., YILMAZ N. and BOEHM C.

Cheers

François

[Thierry Garrel]

Ca c'est du debriefing ! Merci François, ça met en place.

5461 was seen in emission in March 7 spectra, taken at very low altidude, 17°. I have the same emission in the first spectra of my early series at high airmass and it vanished with airmass getting low, from 20° to 70° altitude. It could be an atmospheric emisison.
Note Auroral activities was strong during until March 10,

[Francois Teyssier]

Au LISA ce matin

[Robin Leadbeater]

Note that it is very dificult to identify the Telluric lines (at H alpha for example) because the spectrum is so complex. It is a good idea to take standard hot stars at different elevations at the same time so that the Tellurics can be estimated and removed.

Cheers
Robin

[Thierry Garrel]

It is a telluric line, with fringing pattern beside when present. I have the same in today early morning spectra at 17° above northeast horizon and on one spectra not well guided at 70°high south. Robin It's a good idea but the pro are knowing such lines and does not need a comparison star, difficult to find at same airmass and azimuth, as dibs too. We may ask to Margaritta if there is the needing.
H alpha behavior summary of three days of observations.

[Robin Leadbeater]

Hi Theiry,


Yes the positions of Tellurics are known. Perhaps you can find enough tellurics to measure the intensity of the O2 and H2O lines in the eShel spectra but in my narrow range LHIRES H alpha spectra they not measurable because there are too many other lines masking them. The intensity of the H2O lines in my spectra is therefore not known. Without a measure of intensity they cannot be removed. The standard procedure used by pros in these circumstances is to take hot (line free) stars at two elevations. You can then use these to estimate the intensity of the Tellurics at the elevation of the target. Unless I do this my H alpha spectra will not be reliable.

Cheers
Robin