WZ Cephei
Binary star in the constellation Cepheus
From Wikipedia, the free encyclopedia
WZ Cephei is an eclipsing binary star of W Ursae Majoris-type in the constellation of Cepheus, located 976 light years away from the Sun.[1] The stars orbit around a common orbital barycenter every 0.41744 days (slightly over 10 hours).[3] Timing analyses have revealed the possible presence of a third low-mass stellar companion in a wide orbit.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 23h 22m 24.193s[1] |
| Declination | +72° 54′ 56.83″[1] |
| Apparent magnitude (V) | +11.22 |
| Characteristics | |
| Spectral type | F5V+F5V |
| Variable type | W Ursae Majoris-type |
| Astrometry | |
| Proper motion (μ) | RA: 18.655±0.013[1] mas/yr Dec.: −37.713±0.012[1] mas/yr |
| Parallax (π) | 3.3419±0.0105 mas[1] |
| Distance | 976 ± 3 ly (299.2 ± 0.9 pc) |
| Orbit | |
| Period (P) | 0.00114 yr |
| Semi-major axis (a) | 0.013 AU |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 86.2[2]° |
| Details | |
| A | |
| Mass | 1.1 M☉ |
| Radius | 1.4 R☉ |
| Luminosity | 3 L☉ |
| Temperature | 6400 K |
| B | |
| Mass | 0.83 M☉ |
| Radius | 0.82 R☉ |
| Luminosity | 1 L☉ |
| Other designations | |
| WZ Cep, 2MASS J23222421+7254566, 1RXS J232216.6+725505 | |
| Database references | |
| SIMBAD | data |
Heribert Schneller announced the discovery that the star is a variable star, in 1928.[6]
Presence of a third body
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.[4] 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.
