New Results of VV Cep

[Ernst Pollmann]

Dear colleagues,
herewith I want inform you about the newest evaluation of VV Cep. The growing data set since approx. JD 2459000 did enable a new analysis of the radial velocity of the V emission component.
The question has been, whether the former precession period of 52 day could be improved. See the attached analysis.
Many thanks for your worthwhile spectra!!

Ernst Pollmann

[Ernst Pollmann]

For VV Cep interested observer:
Supplementary Intermediate Report (July 2022) to the Spectroscopic Monitoring of the 2017–2019 Eclipse of VV Cephei

https://app.aavso.org/jaavso/article/3845/

Ernst Pollmann

[Ernst Pollmann]

Dear colleagues!
With the video links below I would like to explain what it is currently about at the VV Cep observation campaign.
The previous multi-year campaign had revealed that the B companion star, with its emitting accretion disk and emission ejections in the star's rotational axis, is subject to a periodic libration on its orbit around the M supergiant. A 40-50 day periodicity was indicated.

However, there was a lack of unmistakable clarity.
The current campaign aims to make this periodicity clear. The (total) Halpha-equivalent width (EW) of the tumbling disk, plus the emission ejections in both directions of the stellar rotation axis, should be a suitable parameter to clearly represent this periodicity.

The video animation "Orbit B-Star" shows schematically the libration of the B star with its accretion disk and emission ejections on the orbit:
https://www.dropbox.com/s/7w8p6p7shbdhy ... r.WMV?dl=0

The video animation "Disk-Libration" illustrates a schematically a disk libration and the variability of the total Halpha EW that can be expected with it.
https://www.dropbox.com/s/3vgfaaie2drna ... n.mp4?dl=0

The attached Fig. shows the current state of results from collaboration spectra from J. Guarro, E. Bertrand, E. Bryssinck, K. Alich and me. The blue curve represents a fit with a period of 41.5 days and confirms impressively the libration of the disk rotational axis. This is a fantastic result of so far unknown properties of VV Cep.
Ernst Pollmann

[etienne bertrand]

Good works Enrst !

A star perctly for survey in the automn-winter ! Accessible for many astronomers, with C11 : 3x300s with godd snr..

[Ernst Pollmann]

Dear colleagues,
our analysis of the libration of the accretion disk and its emission lobes in VV Cep provides in addition to the evaluation of the radial velocity (JAAVSOVolume 50, 2022) additional and further more consistent results (see attachment).
Comments?
Ernst Pollmann