spectro-aras.com

Observations of R Aqr are scheduled by Margarita Karovska
Both low and and res spectra


Thank you for the R Aqr input and information.
It is great that there are already observations covering several years.

Do you have plots similar to the CH Cyg ones (that you have in the newsletter)?

We are having Chandra and HST observations currently scheduled for October 2017.
It will be great we can get photometry and spectroscopy coverage starting soon, and then during the Chandra/HST observations (more dense) and a couple of months after these observations.

She will send us a more explicit text about the campaign

François

See also AAVSO alert notice :
https://aavso.org/aavso-alert-notice-589

A spectrum of this star taken with eshel spectrograph.
Difficult to obtain a good SNR in the blue because the target is about V=8,6 and low in altitude.
The full graph (cut at 4400 because of very poor signal)



H Alpha line : very narrow line with a FWHM about 1,34 Å (61,46 km/s) with a SNR about 115


All emissions lines are narrow like HeI 5876


And TiO lines

Hi Olivier, your spectrum seems to me very good. H-alpha and [O III] lines are in the fair SNR range. I hope to observe it too (like Nova Sct, it follows a low path in the sky that "grazes" the roofs in front of my observatory).

Paolo

My attempt at this star on Aug 10th. About as low as I can reach from my location (unless I cut the tops off some of our trees).
I am pleased with the signal to noise I was able to get in spite of the poor seeing at this low altitude and the lower slit efficiency.
Tim

Hi Tim,

I think you have the same problem on your spectrum than on mine (below 4500 Å). That why I crop my spectrum at this wavelength
I don't think that H gamma and H delta can be greater in flux than H beta and H alpha.
Because the continuum is very low in the blue of the spectrum, the relative intensity of emissions may be false.
Maybe it is real but strange because in principle the Balmers Lines progressively decrease from red to the blue and therefore H Delta must be lower than H gamma it even lower than H beta and H alpha.

Maybe "pros" astronomer could give us information on this ?

Olivier,

Tim's spectrum is correct

R Aqr is D type symbioctic, with a Mira as giant
In Miras spectra, the Balmer decrement is abnomalous, with H delta as the main emission line
see
http://www.astronomie-amateur.fr/feuill ... Miras.html
or
http://www.astronomie-amateur.fr/feuill ... ctres.html

The abnomalous Balmer decrement was first expalaine by the TiO absorption.
Modern theory claims that the lines are produced by chocks in the pulsating atmosphear. The strenght of the lines depend of the deepth at which are formed the lines (optical deepth accompts)

Note that all the lines, comprising Balmer lines are narrow. Their origin is the Mira atmosphere and wind

François

François,

Thank you for this explanation.
So my spectrum is good also below 4600 Å.

Olivier,

Good for calibration and the shape of the lines, notably H gamma
But not for the atmo/instrumental correction. The continuum is too high and thus give an anomalous heigh for H gamma Amicalement,

François

I will try to do better next time, but these last nights, I have a lot of mist on the horizon and variable sky conditions....