VV Cephei up-to-date

VV Cep 2017-2019 Campaign
Moderator for this forum: Ernst Pollmann
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

VV Cephei up-to-date

Post by Ernst Pollmann »

Dear colleagues,
the spectroscopic observations and its results are up dated.
See:
http://astrospectroscopy.de/media/files ... todate.pdf

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

Re: VV Cephei up-to-date

Post by Ernst Pollmann »

Dear colleagues,
here I want to present the current state of observation results of VV Cep.
On the basis of these results, in collaboration with Phil Bennett a new geometrically structure of the emission sources have been developed. This first draft is available as animation (30MB). In case of certain interest please write an email, I will send the password access to the cloud.
vvcep_1.png
vvcep_2.png
vvcep_2.png (597.67 KiB) Viewed 19709 times
Ernst Pollmann
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: VV Cephei up-to-date

Post by Ernst Pollmann »

Dear colleagues,
the gravitational force of the M supergiant exerts a forced angular momentum on the B star disk that triggers the 45-day precession period of the disk rotational axis. But a precessing disk rotation axis with a period of 45 days, would inevitably have to result in a simultaneous variation of radial velocity of the V(max) flux. Precise radial velocity (RV) measurements of the Hα V component, based on LHIRES III spectra of the ARAS observers (Schwarz, Kalbermatten, Bryssinck, Foster, Bertrand, Sawicki, Martin, Stiewing, Pollmann) seem to confirm the periodic precession movement of the B star disk rotational axis.

The first signs of such a movement have been discovered during the period analysis of the flux and EW time behavior of the Hα V and R components. Because of the small average RV amplitude of approx. (+/-) 1.7 km/s, this is not as simple as it seems. In spite of the high accuracy in wavelength calibration (order 10-3 to 10-4 Angströms) by using the new program SpectroCalc (developed by M. Schwarz, Austria), the error in RV is in the range of (+/-) 3 km/s in one observation night. All spectra have been calibrated with metal lines of the M star around Hα:

FeI 6546.245
TiI 6556.066
CaI 6572.781
FeI 6593.878

This method of calibration led to a radial velocity relative to the M star and without any influence of the system velocity. But the period of approx. 51 days still is unclear at this time, compared to 45 days found in analysis of the precession period of the disk rotational axis.
The upper plot shows the monitoring of RV measurements from 220 spectra from January 2018 to June 2019. The period analysis of the detrended RV data (in the upper plot) shows the plot in the middle, and finally the phase diagram of the found period of 50.9 days is shown in the plot bottom.
To better understand the RV of the V(max) flux, I recommend looking at the orbital animation, which I can send upon request.
conclusion.png
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Ernst Pollmann
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: VV Cephei up-to-date

Post by Ernst Pollmann »

Dear colleagues,
the current state of the ARAS campaign observation results seems to explain the periodic time behavior of the equivalent width and the flux of the Halpha emission components V & R.
See:
https://astrospectroscopy.de/News

Ernst Pollmann
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: VV Cephei up-to-date

Post by Joan Guarro Flo »

Hallo Ernst,

Many thanks for your explanations, I'm going to observe this star.

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

Re: VV Cephei up-to-date

Post by Ernst Pollmann »

Dear colleagues,
a lot of new spectra did enable an up date of the "state of the art" of VV Cep. See:
https://astrospectroscopy.de/News

Many thanks to all the colleagues who contributed with their spectra:
more than 900 for V and R analysis !!
more than 280 for Radial velocity analysis !!

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

Re: VV Cephei up-to-date

Post by Ernst Pollmann »

For friends of pretty pictures in spectroscopy:
a "nice overview" of the newly-discovered 43 day period of the both emission lobes above (the blue V emission) and underneath (the red R emission) the accretion disk in VV Cep out of eclipse. To draw this nice Figure was only possible on basis of the high spectra cadence of Carl Sawicki, Al Stiewing, Eric Bryssinck, Jack Martin, Juan Guarro and me. Many thanks to them!!
VV Cep.png
emissionlobes in VV Cep.jpg
Ernst Pollmann
Jack Martin
Posts: 54
Joined: Fri Sep 11, 2015 10:31 am

Re: VV Cephei up-to-date

Post by Jack Martin »

Ernst,

I have been monitoring the H alpha line of VV Cep since 26_08_2015, approximately 140 nights of data.

This discovery clearly demonstrates how amateurs can make a valuable contribution, on a professional level, through international collaboration.

An excellent result and very rewarding for everybody who submitted data.

Clear skies to all,

Jack Martin

Essex UK
Benjamin Mauclaire
Posts: 258
Joined: Thu Sep 29, 2011 10:14 am

Re: VV Cephei up-to-date

Post by Benjamin Mauclaire »

Hi Jack,

In aras db there are only 10 UK spectra.
Your data is missing to Ernst!
Where are your processed spectra?
Is there a traffic jam?

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
Contact:

Re: VV Cephei up-to-date

Post by Robin Leadbeater »

Hi Benji
Benjamin Mauclaire wrote:Hi Jack,
In aras db there are only 10 UK spectra.
There are about 350 spectra in the BAA database for VV Cep. Some will be duplicates but there are about 150 spectra from uk observers. (Many cover other wavelengths than H alpha) None are from Jack though

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