Astron. Astrophys. 349, 511-514 (1999)

The 1997/1998 eclipse of VV Cephei was late

L. Leedjärv ¹, D. Graczyk ², M. Mikoajewski ² and A. Puss <sup>1,3

1</sup> Tartu Observatory, 61602 Tõravere, Estonia (leed@aai.ee)
² Centre for Astronomy, Nicolaus Copernicus University, ul. Gagarina 11, PL-87 100 Toru, Poland (weganin, mamiko@astri.uni.torun.pl)
³ Department of Physics, Tartu University, 4 Tähe Street, 51010 Tartu, Estonia (alar@aai.ee)

Received 21 June 1999 / Accepted 19 July 1999

Abstract

The recent eclipse of the long-period () binary star VV Cephei is studied by means of UBV photometry and optical spectroscopy. Both photometry and variations of the emission lines (H and FeII 4233) show that the eclipse occured about 68 days later than predicted from the ephemeris. Such a sudden about 1% lengthening of the orbital period between the last two eclipses implies that the generally accepted model of VV Cep with the masses of both the M supergiant and the hot B star of about 20 should be revised. The period change due to mass transfer between the components or mass ejection from the VV Cep system can be explained, if one accepts the medium mass model for VV Cep, with the mass of the M star about 2.5 and of the B star about 8 . This model implies that the cool component of VV Cep could be an AGB star rather than a supergiant.

Key words: stars: binaries: eclipsing stars: individual: VV Cep stars: supergiants

Send offprint requests to: L. Leedjärv (leed@aai.ee)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Photometry
• 3. Spectroscopy
  • 3.1. Observations
  • 3.2. H line
  • 3.3. Permitted and forbidden lines of FeII
• 4. Discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: September 2, 1999
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