Global InformationVV Cephei information
 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] |
| Distance | 3,319+463 −323 – 4900 ly (1,018+142 −99[7] – 1500[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[11] AU) |
| Eccentricity (e) | 0.346 ± 0.01[10] |
| Inclination (i) | 84[8]° |
| Semi-amplitude (K1) (primary) | 19.43 ± 0.33[10] km/s |
| Semi-amplitude (K2) (secondary) | 19.14 ± 0.68[10] km/s |
| Details | |
| A | |
| Mass | 18.2[11] or 2.5[12] M☉ |
| Radius | 779+77 −96,[13]1,050[8] R☉ |
| Luminosity | 116,000[14] L☉ |
| Surface gravity (log g) | –0.26[14] cgs |
| Temperature | 3,660[15] (3,480[16] – 3,826[2]) K |
| Metallicity [Fe/H] | −0.06[17] dex |
| Age | 25±0.1[18] Myr |
| B | |
| Mass | 18.6[11] or 8[12] M☉ |
| Radius | 13[10] or 25[19] R☉ |
| Metallicity [Fe/H] | −0.14[20] dex |
| Age | 25±0.1[18] 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 | |
| SIMBAD | data |
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 780 R☉ to over 1,000 R☉.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Cite error: The named reference
keenanwas invoked but never defined (see the help page). - ^ 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.
- ^ Cite error: The named reference
b-hwas invoked but never defined (see the help page). - ^ a b c 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.
- ^ 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.
- ^ a b c d e Cite error: The named reference
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runawaywas invoked but never defined (see the help page). - ^ 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.
- ^ 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.