Campaign Halpa RV of gamma Cas

[Ernst Pollmann]

Dear colleagues,
as you already know, several ARAS observers take part successful at the Halpha RV campaign, in order to determine the orbital eccentricity in the sense: zero or not zero (that's here the question).
At present we are on the ascending RV branch, and it would be great, if further observers could contribute with high-resolution spectra (for example LHIRES, 2400) to that campain.

Best wishes, Ernst Pollmann
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International Working Group ASPA
Active Spectroscopy in Astronomy
http://www.astrospectroscopy.de
http://www.astronomie.de/astronomische- ... troskopie/

[Ernst Pollmann]

Dear colleagues,
here an information about the current observation state of the campaign.

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues,
I would like to inform you about the ongoing monitoring of the radial velocity of gamma Cas.
Particularly the continuous observations of Patrik Fosanelli, emphasizes the (un-expected) second distortion (this time) in the descending branch of the velocity curve. I will inform our professional partners (A. Miroshnichenko & M. Smith) about that phenomenon.

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues,
herewith I would like to inform you (particularly A. Wilson, T. Lester, P. Fosanelli, M. Schwarz, C. Sawicki, J.N. Terry, P. Berardi, Th. Lemoult because of their current BeSS spectra) about the current RV characteristics of gamma Cas.
My impression is that the RV scatter became larger (caused by further disk re-structuring) since the last maximum around JD 2457250.

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues!
For a certain reason I want come back to the importance of the observation of the Halpha radial velocity in gamma Cas (see postings above).
Even if some observers believe, that it would be not necessary to observe frequently this "well known" (?) Be binary star, there are phenomenons in its radial velocity which required exactly the opposite.
We found at a certain time an irregularity in the sinusoidal course of the RV, which our professional consulters interpreted as indicator of a changes in the morphology of a no longer perfectly axis-symmetric disk. See the attached comments of the experts Dr. Myron Smith and Prof. Dr. Anatoly Miroshnichenko.

Report to ARAS.png (128.46 KiB) Viewed 1507 times

And when we receive ideally one spectrum/day, then we would be able in case of the repetition of our earlier observation to judge, whether it is a real disturbance in RV, or observation errors.
In that sense I want to encourage all interested Be star observers, not to neglect observations of this system, in a high spectral resolved mode.

Ernst Pollmann