HeI 6678 Campaign of gamma Cas

[Ernst Pollmann]

Dear colleagues,
I think it is time to inform you about the current state of our HeI6678 project of gamma Cas. The following link enables you to download the summary text and corresponding diagrams and files mentioned in it:

https://www.magentacloud.de/share/9v5nz56i.c

To open the file please use the password: 1gam2cas3

Since it is not possible to attach pdf files here in forum postings I have to use this way.

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues,
interesting campaign results.
See:
https://www.aavso.org/gam-cas-campaign-01#comment-74909

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues,
our professional consulter Dr. Myron Smith wrote recently:
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Based on your work on correlation of Halpha and HeI6678 EW´s (see the Fig. below) , it is clear that gCas is in a state now of rapidly building up its disk.
This is a condition for which a proposal a few of us wrote recently for XMM (x-ray satellite) time could fulfill.
The star becomes visible to the satellite once again on January 6th.
Do you think a short time before this we could get a very up to date description of what the star is doing (Christmas-New Years Day timeframe)? We would really appreciate it.
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Gamma Cas (often categorized as uninteresting and well known star) shows at present a high interesting, not only for professionals, but for amateurs too an unique developement, that could end (very soon?) in a super nova event (or so).

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues,
the EW correlation of the (photospheric) HeI6678 emission to the Halpha disk emission is becoming increasingly clear.
The question is how long this will continue and what will happen to gamma Cas.
Many thanks to the involved colleagues to contributes with their spectra.

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues,
X-ray satellite observations (called XMM) are plant until early January by Gregor Rauw and Myron Smith.
Myron wrote yesterday:
"So I hope your group can start working on the star after Christmas into the Fourth of January or so (“10 Days of Christmas”)".

Ernst Pollmann

[Jack Martin]

Here is my effort.

Any comments ?

Regards,

Jack

Essex UK

GamCasHe1.JPG (71.2 KiB) Viewed 60930 times

[Jack Martin]

Interesting absorption feature around 663.5nm now fading.

Any comments ?

Jack

Essex UK

gamcasabsorption.JPG (71.35 KiB) Viewed 60708 times

[J Labadie Bartz]

Hi Jack,

Weird feature. Do you think it is real (in the sense that it is astrophysical and not some detector artifact)? I took spectra of gamma Cas on the night of Jan 15 (UT time ~01:30 Jan 16) and there is no sign of this feature in my sequence of 13 exposures. There shouldn't be any photospheric absorption at that wavelength for an early B-type star. However our data seem to have good agreement in the shape of the He 6678 line profile.

Single exposure from night of Jan. 15.

gamma_Cas_plot_25.png (103.16 KiB) Viewed 60632 times

[Robin Leadbeater]

Hi Jack,

Dust specs and a poor flat correction perhaps ? Is the spectrum in the same Y position on the sensor for all these observations? Is it on all the sub exposures ? What does the reference star spectrum look like ?

Cheers
Robin

[Jack Martin]

JLB,

As you have not detected it in your observations, I don't think its real, an artifact of the set up.

Thanks for your input.

Jack

Essex UK