WZ Cephei

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WZ Cephei
WZ Cephei binary.png
Artist's impression of WZ Cephei, eclipsing binary of W UMa-type.
Observation data
Epoch {{{epoch}}}      Equinox
Constellation Cepheus
Right ascension 23h 22m 24.215s
Declination +72° 54′ 56.70″
Apparent magnitude (V) +11.22
Spectral type F5V+F5V
Variable type W Ursae Majoris-type
Distance 880.2 ly
(270[1] pc)
Mass 1.1/0.83 M
Radius 1.4/0.82 R
Luminosity 3/1 L
Temperature 6400 K
Period (P) 0.00114 yr
Semi-major axis (a) 0.013Astronomical Units"
Eccentricity (e) 0.0
Inclination (i) 86.2[2]°
Other designations
V* WZ Cep, 2MASS J23222421+7254566, [GGM2006] 182244, AN 244.1928, 1RXS J232216.6+725505
Database references

WZ Cephei is an eclipsing binary star of W Ursae Majoris-type in the constellation of Cepheus, located 880 light years away from the Sun. The stars orbit around a common orbital barycenter every 0.41744 days (slightly over 10 hours). Timing analyses have revealed the possible presence of a third low-mass stellar companion in a wide orbit.[3]

Presence of a third body[edit]

According to Zhu & Qian (2009) a third low-mass object of stellar nature could be responsible of orbital period variations observed for WZ Cep with a periodicity of roughly 32 years.[3] Such a companion would yield a minimum mass of 0.17 Solar masses and be located 26.6 Astronomical Units (nearly the same orbital separation of Neptune in Solar System) from the eclipsing binary. The star could likely turn out a Proxima Centauri-analog, with inferred luminosity 3.7 percent that of Sun and 20 percent of its radius, according to mass-radius relationship.


  1. ^ Geske; Gettel, S. J.; McKay, T. A. (2006). "A ROSAT Survey of Contact Binary Stars". The Astronomical Journal. 131 (1): 633–637. arXiv:astro-ph/0509820free to read. Bibcode:2006AJ....131..633G. doi:10.1086/498018. 
  2. ^ Djurasevic; Zakirov, M.; Hojaev, A.; Arzumanyants, G. (1998). "Analysis of the activity of the eclipsing binary WZ Cephei". Astronomy and Astrophysics Supplement. 131 (1): 17–23. Bibcode:1998A&AS..131...17D. doi:10.1051/aas:1998248. 
  3. ^ a b Zhu & Qian (2009). "WZ Cephei: A Close Binary at the Beginning of Contact Phase". Astronomy and Astrophysics Supplement. 138 (6): 2002–2006. Bibcode:2009AJ....138.2002Z. doi:10.1088/0004-6256/138/6/2002.