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The long-period binary VV Cep

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Ernst Pollmann's picture
Ernst Pollmann
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Joined: 2012-02-03

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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Active Spectroscopy in Astronomy

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VV Cep
HPO's picture
HPO
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Joined: 2010-07-23

 

Thank you  Ernst.

VV Cep is a very interesting star system, second only to Epsion Aurigae as the longest known eclipsing binary star system with a period of about 20 years and the next eclipse due in 2017. Out-of-eclipse it shines at V= 4.91. Dr. Philip Bennett has been following this system in detail.

For more information see:

http://www.hposoft.com/Astro/PEP/VVCephei.html

Jeff

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484