Rho Cas Activity

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Christophe Boussin
Posts: 170
Joined: Sun Aug 21, 2016 6:04 pm

Re: Rho Cas Activity

Post by Christophe Boussin »

Hello all,

Here is my contribution to this very interesting monitoring of the Rho Cas activity.

I obtained previously a high resolution spectrum around the Halpha line of Rho Cas on July 8 at 1 h 20 TU (resolution of 17942, JJ = 2459403.5552, 6 x 600s) and recently two new spectra on October 19 at 20 h 19 TU (resolution of 19325, JJ = 2459507.3467, 7 x 600s), and on October 27 at 18 h 35 TU (resolution of 18778, JJ = 2459515.435, 6 x 600s) with my LHIRES III (grating of 2400 lines / mm).

Here is the comparison between these three spectra (the positions of the telluric lines are indicated using the PlotSpectra software) :
Spectral domain around the Halpha line of Rho Cas on July 8th and October 19th and 27th 2021
Spectral domain around the Halpha line of Rho Cas on July 8th and October 19th and 27th 2021
As reported by Ernst Pollmann in the previous post, the profile of Rho Cas Halpha line has clearly evolved in recent months. This evolution is well visible between my spectra of July 8 and October 19 but I don't notice any significant change between those of October 19 and 27.

Here is a more detailed view around the Halpha line of Rho Cas :
Spectral domain around the Halpha line of Rho Cas on July 8th and October 19th and 27th 2021 (zoom)
Spectral domain around the Halpha line of Rho Cas on July 8th and October 19th and 27th 2021 (zoom)
rhocas_20210708_20211027_Halpha_zoom_Christophe Boussin.png (23.82 KiB) Viewed 7960 times
Please note that the spectra are not corrected for heliocentric radial velocity (according to the ISIS software, the values are as follows : 17.880 km/s on July 8 ; 1.408 km/s on October 19 (the movement of the Earth brings us closer to Rho Cas for these 2 dates) and -1.192 km/s on October 27 (the movement of the Earth takes us away from Rho Cas for this last date).

Zero velocity is on Halpha 6562.801 A at rest, and, according to Klochkova et al. (2014), https://arxiv.org/pdf/1312.6922v1.pdf, the systemic velocity is −47 km/s (which means here that Rho Cas and the Sun are moving towards each other) and due to low amplitude pulsations of the atmospheric layers near the photosphere, the radial velocity varies with an amplitude of about 7 km/s around this value.

Clear skies to all !!

Christophe BOUSSIN
CBO (Newton 200 F/5 / Alpy600 / Atik 314L+ / Atik Titan + Mewlon 180 F/12 / LHIRES III 2400 / Atik 460EX / Atik 314 L+) @ ARAS database
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: Rho Cas Activity

Post by Ernst Pollmann »

Monitoring of the ejection behavior of Rho Cas; Line flux and radial velocity of the Hα double peak emission

Our previous observation efforts to describe scientifically relevant radial velocities and emission fluxes in the Hα range do not seem to me from today's point of view and especially in view of our previous monitoring, to correspond to the research goals of professional astronomy.
According to Klochkova et al. we have also concentrated on the ejection process in the Hα range, because photospherical ejections are evidently particularly easy to detect in this spectral range. As before, our main focus is therefore still on the intensity behavior of the blue- and red-shifted Hα emissions, but now is supplemented by their radial velocity behavior (RV), which is why all the spectra provided by all observers involved in the Hα emission line profile have been re-evaluated. See:

https://astrospectroscopy.de/.cm4all/up ... 7db86c476b

Ernst Pollmann
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: Rho Cas Activity

Post by Ernst Pollmann »

Dear colleagues,
our rho Cas monitoring, particularly the behavior of the red emission component seems to reveal as monthly average time behavior a cyclical variability of its radial velocity with a period of 216 days (see the attached plot).
If I am informed right, such a cyclical property of the radial velocity of the red emission component has been unknow so far.
Against that background it makes sense to continue the observations of the star.
Ernst Pollmann
Radial-Velocity Red Emission.png
Radial-Velocity Red Emission.png (142.03 KiB) Viewed 7305 times
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: Rho Cas Activity

Post by Joan Guarro Flo »

Hallo Ernst,

I'm stopped due at bad weather..

Cheers, Joan.
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
Contact:

Re: Rho Cas Activity

Post by Robin Leadbeater »

Where can I find the spectra of Rho Cas please? I can see the ones in the BAA database but there are none in the ARAS database so there must be more I think

Thanks
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: Rho Cas Activity

Post by Ernst Pollmann »

... at the AAVSO data base:

https://app.aavso.org/avspec/search

Ernst
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
Contact:

Re: Rho Cas Activity

Post by Robin Leadbeater »

Ernst Pollmann wrote:... at the AAVSO data base:

https://app.aavso.org/avspec/search

Ernst
Thanks
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
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