Epsilon Ceti
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 39m 33.79741s |
| Declination | −11° 52′ 19.5516″ |
| Apparent magnitude (V) | +4.84 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | F2V + F7/G4V |
| U−B color index | −0.02 |
| B−V color index | +0.45 |
| Astrometry | |
| Radial velocity (Rv) | 15.49±0.19 km/s |
| Proper motion (μ) | RA: +167.071 mas/yr Dec.: −251.104 mas/yr |
| Parallax (π) | 41.43±0.68 mas |
| Distance | 79 ± 1 ly (24.1 ± 0.4 pc) |
| Absolute magnitude (MV) | +2.68 |
| Orbit | |
| Period (P) | 2.6512±0.0005 yr |
| Semi-major axis (a) | 0.1063±0.0005″ |
| Eccentricity (e) | 0.230±0.001 |
| Inclination (i) | 24.2±0.2° |
| Longitude of the node (Ω) | 90.2±0.2° |
| Periastron epoch (T) | 2,012.3109±0.0005 |
| Argument of periastron (ω) (secondary) | 40.8±0.2° |
| Details | |
| ε Cet A | |
| Mass | 1.37±0.09 M☉ |
| Radius | 1.52 R☉ |
| Surface gravity (log g) | 4.21±0.14 cgs |
| Temperature | 6,520 K |
| Metallicity [Fe/H] | −0.08 dex |
| Rotational velocity (v sin i) | 11.5 km/s |
| Age | 1.8 Gyr |
| ε Cet B | |
| Mass | 1.03±0.08 M☉ |
| Radius | 1.27 R☉ |
| Temperature | 6,370 K |
| Metallicity [Fe/H] | −0.08 dex |
| Rotational velocity (v sin i) | 2.0 km/s |
| Other designations | |
| ε Cet, 83 Cet, BD−12°501, GJ 9091, GJ 105.4, HD 16620, HIP 12390, HR 781, SAO 148528 | |
| Database references | |
| SIMBAD | data |
Epsilon Ceti is a binary star system located in the equatorial constellation of Cetus. Its name is a Bayer designation that is Latinized from ε Ceti and abbreviated Epsilon Cet or ε Cet. This system is faintly visible to the naked eye as a point of light with an apparent visual magnitude of +4.84. Based upon an annual parallax shift of 41.43 mas, it is located around 79 light-years away from the Sun.
This is a line-width spectroscopic binary star system. It has an orbital period of 2.65 years and an eccentricity of 0.23. The semimajor axis is 0.11 AU, or 11% of the distance between the Sun and the Earth, and the orbital plane is inclined at an angle of 24.2° to the plane of the sky.
The primary member, component A, is an F-type main-sequence star with a stellar classification of F2 V. The spectrum of the secondary, component B, can not be readily separated from that of the primary, so its type can only be estimated as a main-sequence star lying in the range between F7 V and G4 V. The system is estimated to be 1.8 billion years old, with the primary having 1.4 times the mass of the Sun and the secondary being about equal to the Sun's mass.