Epsilon Ceti
Location of ε Ceti (circled in red) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 39m 33.79741s[1] |
| Declination | −11° 52′ 19.5516″[1] |
| Apparent magnitude (V) | +4.84[2] |
| Characteristics | |
| Spectral type | F2V + F7/G4V[3] |
| U−B color index | −0.02[2] |
| B−V color index | +0.45[2] |
| Astrometry | |
| Proper motion (μ) | RA: +167.071 mas/yr[1] Dec.: −251.104 mas/yr[1] |
| Parallax (π) | 41.43±0.68 mas[3] |
| Distance | 79 ± 1 ly (24.1 ± 0.4 pc) |
| Absolute magnitude (MV) | +2.68[4] |
| Orbit[3] | |
| 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[3] M☉ |
| Radius | 1.52[5] R☉ |
| Surface gravity (log g) | 4.21±0.14[6] cgs |
| Temperature | 6,520[5] K |
| Metallicity [Fe/H] | −0.08[5] dex |
| Rotational velocity (v sin i) | 11.5[5] km/s |
| Age | 1.8[6] Gyr |
| ε Cet B | |
| Mass | 1.03±0.08[3] M☉ |
| Radius | 1.27[5] R☉ |
| Temperature | 6,370[5] K |
| Metallicity [Fe/H] | −0.08[5] dex |
| Rotational velocity (v sin i) | 2.0[5] km/s |
| Other designations | |
| ε Cet, 83 Cet, BD−12°501, GJ 9091, GJ 105.4, HD 16620, HIP 12390, HR 781, SAO 148528[7] | |
| Database references | |
| SIMBAD | data |
Epsilon Ceti, Latinized from ε Ceti, is a binary star system located in the equatorial constellation of Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of +4.84.[2] Based upon an annual parallax shift of 41.43 mas,[3] 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°.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.[3] The system is estimated to be 1.8 billion years old,[6] with the primary having 1.4 times the mass of the Sun and the secondary being about equal to the Sun's mass.[3]
Name
[edit | edit source]This star, along with π Cet, ρ Cet and σ Cet, was Al Sufi's Al Sadr al Ḳaiṭos, the Whale's Breast.[8]
According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Sadr al Ḳaiṭos were the title for four stars: ρ Cet as Al Sadr al Ḳaiṭos I, σ Cet as Al Sadr al Ḳaiṭos II, this star (ε Cet) as Al Sadr al Ḳaiṭos III and π Cet as Al Sadr al Ḳaiṭos IV.[9]
In Chinese, 芻蒿 (Chú Hāo), meaning Hay, refers to an asterism consisting of ε Ceti, ρ Ceti, 77 Ceti, 67 Ceti, 71 Ceti and HD 14691.[10] Consequently, the Chinese name for ε Ceti itself is 芻蒿六 (Chú Hāo liù, English: the Sixth Star of Celestial Meadows).[11]
References
[edit | edit source]- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
- ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f g h Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f g h Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
- ^ (in Chinese) 夢之大地 @ 國立成功大學 WebBBS DreamLand @ National Cheng Kung University WebBBS System
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 12 日 Archived 2011-05-22 at the Wayback Machine
