The long-period binary VV Cep

Dear colleages,

addressed to interested observers, I would like to remind, not forget to observe the long-period binary VV Cep (Fig. 1).

Some observers provided in 2012 spectra, which supplemented the EW and V/R monitoring (Fig. 3 & 4). The V/R monitoring covers in the meantime the period Aug. 1999 until now, but there is a lack from phase 0.43 to 0.74 of the 7430 d orbital period (Fig. 2 & 5).

The Halpha spectra in Fig. 2 shows the V/R variation very clearly, depending on the orbital phase. This V/R ratio reflects the process of disk feeding by the M super giant around the periastron and the dispersion of this matter within the disk, depending on phase (Fig. 4  & 5).

The process of dispersion is linked with a disk rotation (period approx. 1000 days). Fig. 6 & 7 shows the V/R time series itself and its long-term removed residuals, Fig. 8 & 9 the period analysis and phase plot respectively. The result of the period analysis is not satisfying, because of the bad ratio amplitude/RMS.

It would be great, if interested observers could contribute to this long-term monitoring.

Ernst Pollmann

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