spectro-aras.com

Version Française juste dessous :
This night, I just take the spectrum of CX Dra and the H alpha line is not in emission

Here is the graph that compares my spectrum of June 22th with the spectrum taken now.

Je viens de faire le spectre de CX Dra et la raie H alpha n'est plus en emission (comme lors de mon dernier spectre du 22 juin 2016)
Voici le graphe qui compare mon spectre du 22 juin avec celui réalisé à l'instant.

And the H Beta line

Last change in H alpha line for CX Dra, here's a graph show the evolution of H Alpha line since 2014.
Last spectrum of 4th october show emission line again compare to a spectrum taken in jully 2016 in absorption.

Un spectre de CX Dra réalisé le 4 octobre dernier montre que la raie H Alpha est de nouveau en émission alors qu'elle était en absorption en juillet dernier.

Salut Olivier

Yes cx dra is a star which has a profile which evolves quite often. In fact it is a Binary star B3+F5III
Here is the summary view for all the BeSS spectra - evolutions from day to day can be observed. Would worth a look at litterature.
V.-

Last spectrum of CX Dra taken 2 nights ago and evolution since my last observation
H-Alpha

H-Beta


And evolution from all my data since 2014

Another spectrum taken last night show the H Alpha line increase and also some change in H beta.

Last change in CX Dra spectrum

Comparison with the last spectrum in BESS taken one month ago

Another observation of this Be star (comparison with the last spectrum in BESS database)


and the last 7 spectra of this Be star

Last evolution of CX Dra

Last observation of CX Dra and comparison with my last spectrum of october 17th.