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VV Cephei

Not to be confused with W Cephei or V Cephei.

VV Cephei

Location of VV Cephei in Cepheus constellation
Observation data
Epoch J2000      Equinox J2000
Constellation Cepheus
Right ascension 21h 56m 39.14385s[1]
Declination +63° 37′ 32.0174″[1]
Apparent magnitude (V) 4.91[2] (4.80 - 5.36[3])
Characteristics
U−B color index +0.43[4]
B−V color index +1.73[4]
Variable type EA + SRc[3]
A
Evolutionary stage Red supergiant
Spectral type M2 Iab[2] (M1p 0)[5]
U−B color index +2.07[4]
B−V color index +1.82[4]
B
Evolutionary stage B-type main-sequence star
Spectral type B0-2 V[2]
U−B color index −0.52[4]
B−V color index +0.36[4]
Astrometry
Proper motion (μ) RA: −1.066[6] mas/yr
Dec.: −0.425[6] mas/yr
Parallax (π)1.0033 ± 0.1073 mas[6]
Distance3,319 – 4900 ly
(1,018+142
−99[7] – 1500±400[8] pc)
Absolute magnitude (MV)−6.93[9]
Orbit
Period (P)7,430.5 days[10]
Semi-major axis (a)16.2 ± 3.7[2]"
(24.8[8] AU)
Eccentricity (e)0.346 ± 0.01[10]
Inclination (i)84[11]°
Semi-amplitude (K1)
(primary)		19.43 ± 0.33[10] km/s
Semi-amplitude (K2)
(secondary)		19.14 ± 0.68[10] km/s
Details
A
Mass2.5[12] or 18.2[8] M☉
Radius660,[13] 1,050[11] R☉
Luminosity72,880±16,300[14] L☉
Surface gravity (log g)–0.26[15] cgs
Temperature3,660[13] – 3,826[2] K
Metallicity [Fe/H]−0.06[16] dex
Age25±0.1[17] Myr
B
Mass8[12] or 18.6[8] M☉
Radius13[10] or 25[18] R☉
Metallicity [Fe/H]−0.14[19] dex
Age25±0.1[17] Myr
Other designations
VV Cep, HR 8383, HIP 108317, HD 208816, BD+62°2007, WDS J21567+6338, 2MASS J21563917+6337319, IRAS 21552+6323, AAVSO 2153+63, Gaia DR3 2216536246703152256, Gaia DR2 2216536246703152256
Database references
SIMBADdata

VV Cephei, also known as HD 208816, is an eclipsing binary star system located in the constellation Cepheus. It is both a B[e] star and shell star.

VV Cephei is an eclipsing binary with the third longest known period. A red supergiant fills its Roche lobe when closest to a companion blue star, the latter appearing to be on the main sequence. Matter flows from the red supergiant onto the blue companion for at least part of the orbit and the hot star is obscured by a large disk of material. The supergiant primary, known as VV Cephei A, is currently recognised as one of the largest stars in the galaxy although its size is not certain. Estimates range from 660 R☉ to over 1,000 R☉.

  1. ^ a b Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. ^ a b c d e Hopkins, Jeffrey L.; Bennett, Philip D.; Pollmann, Ernst (2015). "VV Cephei Eclipse Campaign 2017/19". The Society for Astronomical Sciences 34th Annual Symposium on Telescope Science. Published by Society for Astronomical Sciences. 34: 83. Bibcode:2015SASS...34...83H.
  3. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  4. ^ a b c d e f Graczyk, D.; Mikolajewski, M.; Janowski, J. L. (1999). "The Sudden Period Change of VV Cephei". Information Bulletin on Variable Stars. 4679: 1. Bibcode:1999IBVS.4679....1G.
  5. ^ Keenan, Philip C. (1942-05-01). "Luminosities of the M-Type Variables of Small Range". The Astrophysical Journal. 95: 461. Bibcode:1942ApJ....95..461K. doi:10.1086/144418. ISSN 0004-637X.
  6. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  7. ^ Cite error: The named reference b-h was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference bennett was invoked but never defined (see the help page).
  9. ^ Ginestet, N.; Carquillat, J. M. (2002). "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components". The Astrophysical Journal Supplement Series. 143 (2): 513. Bibcode:2002ApJS..143..513G. doi:10.1086/342942.
  10. ^ a b c d e Cite error: The named reference wright was invoked but never defined (see the help page).
  11. ^ a b Bauer, W. H.; Gull, T. R.; Bennett, P. D. (2008). "Spatial Extension in the Ultraviolet Spectrum of Vv Cephei". The Astronomical Journal. 136 (3): 1312. Bibcode:2008AJ....136.1312H. doi:10.1088/0004-6256/136/3/1312. S2CID 119404901.
  12. ^ a b Cite error: The named reference late was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference healy was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference baines2021 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Ayres2023 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference carr was invoked but never defined (see the help page).
  17. ^ a b Cite error: The named reference runaway was invoked but never defined (see the help page).
  18. ^ Hack, M.; Engin, S.; Yilmaz, N.; Sedmak, G.; Rusconi, L.; Boehm, C. (1992). "Spectroscopic study of the atmospheric eclipsing binary VV Cephei". Astronomy and Astrophysics Supplement Series. 95: 589. Bibcode:1992A&AS...95..589H.
  19. ^ Ramírez, Solange V.; Sellgren, K.; Carr, John S.; Balachandran, Suchitra C.; Blum, Robert; Terndrup, Donald M.; Steed, Adam (2000). "Stellar Iron Abundances at the Galactic Center". The Astrophysical Journal. 537 (1): 205–220. arXiv:astro-ph/0002062. Bibcode:2000ApJ...537..205R. doi:10.1086/309022. S2CID 14713550.

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