Theta Ceti
Location of θ Ceti (circled in red) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 01h 24m 01.40328s[1] |
| Declination | −08° 10′ 59.7392″[1] |
| Apparent magnitude (V) | 3.60[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | K0 III[4] |
| B−V color index | +1.07[2] |
| Astrometry | |
| Radial velocity (Rv) | +17.2±0.5[5] km/s |
| Proper motion (μ) | RA: −76.226 mas/yr[1] Dec.: −201.519 mas/yr[1] |
| Parallax (π) | 29.0339±0.2198 mas[1] |
| Distance | 112.3 ± 0.9 ly (34.4 ± 0.3 pc) |
| Absolute magnitude (MV) | +0.89[6] |
| Details | |
| Mass | 1.80[7] M☉ |
| Radius | 10.37±0.09[8] R☉ |
| Luminosity | 58.3±3.0[8] L☉ |
| Surface gravity (log g) | 2.70[2] cgs |
| Temperature | 4,951±64[8] K |
| Metallicity [Fe/H] | −0.13±0.15[2] dex |
| Rotational velocity (v sin i) | 2.60[2] km/s |
| Age | 2.20[7] Gyr |
| Other designations | |
| θ Cet, 45 Cet, BD−08°244, FK5 47, HD 8512, HIP 6537, HR 402, SAO 129274[9] | |
| Database references | |
| SIMBAD | data |
Theta Ceti, Latinized from θ Ceti, is a solitary,[10] orange-hued star in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 3.60.[2] Based upon an annual parallax shift of 20.04 mas as seen from Earth,[1] it is located about 113 light-years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.28 due to interstellar dust.[8]
With an age of about 2.2 billion years,[7] this is an evolved, K-type giant star with a stellar classification of K0 III.[4] It is a red clump[3] star on the horizontal branch,[2] which means it is generating energy through helium fusion at its core.[3] The star has an estimated 1.8[7] times the mass of the Sun and has expanded to 10 times the Sun's radius. It is radiating 58 times the solar luminosity from its photosphere at an effective temperature of 4,951 K.[8]
Name
[edit | edit source]In the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, this star was designated Thanih al Naamat (ثاني النعامات - thānī al-naʽāmāt), which was translated into Latin as Secunda Struthionum, meaning the second ostrich.[11] This star, along with η Cet (Deneb Algenubi), τ Cet (Thalath Al Naamat), ζ Cet (Baten Kaitos) and υ Cet, were Al Naʽāmāt (النعامات), the Hen Ostriches.[12][13]
In Chinese, 天倉 (Tiān Cāng), meaning Square Celestial Granary, refers to an asterism consisting of θ Ceti, ι Ceti, η Ceti, ζ Ceti, τ Ceti and 57 Ceti.[14] Consequently, the Chinese name for θ Ceti itself is 天倉三 (Tiān Cāng sān, English: the Third Star of Square Celestial Granary).[15]
References
[edit | edit source]- ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
- ^ a b c d e f g 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).
- ^ a b 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).
- ^ 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 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).
- ^ 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).
- ^ η Cet as Aoul al Naamat or Prima Struthionum (the first ostrich), θ Cet as Thanih al Naamat or Secunda Struthionum (the second ostrich), τ Cet as Thalath al Naamat or Tertia Struthionum (the third ostrich), and ζ Cet as Rabah al Naamat or Quarta Struthionum (the fourth ostrich). υ Cet should be Khamis al Naamat or Quinta Struthionum (the fifth ostrich) consistently, but Al Achsasi Al Mouakket designated the title the fifth ostrich to γ Gam with uncleared consideration.
- ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日 Archived 2011-07-16 at the Wayback Machine
