Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Cetus |
Right ascension | 01h 24m 01.40528s[1] |
Declination | −08° 10′ 59.7212″[1] |
Apparent magnitude (V) | 3.60[2] |
Characteristics | |
Spectral type | K0 III[3] |
B−V color index | +1.07[2] |
Astrometry | |
Radial velocity (Rv) | +17.2±0.5[4] km/s |
Proper motion (μ) | RA: −77.94[1] mas/yr Dec.: −206.53[1] mas/yr |
Parallax (π) | 28.66 ± 0.19 mas[1] |
Distance | 113.8 ± 0.8 ly (34.9 ± 0.2 pc) |
Absolute magnitude (MV) | +0.89[5] |
Details[2] | |
Mass | 1.80[6] M☉ |
Radius | 10.04 R☉ |
Luminosity | 53 L☉ |
Surface gravity (log g) | 2.70 cgs |
Temperature | 4,660±17[6] K |
Metallicity [Fe/H] | −0.13±0.15 dex |
Rotational velocity (v sin i) | 2.60 km/s |
Age | 2.20[6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Theta Ceti, Latinized from θ Ceti, is a solitary,[8] 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 28.66 mas as seen from Earth,[1] it is located about 114 light-years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.10 due to interstellar dust.[2]
With an age of about 2.2 billion years,[6] this is an evolved, K-type giant star with a stellar classification of K0 III.[3] It is a red clump[9] star on the horizontal branch,[2] which means it is generating energy through helium fusion at its core.[9] The star has an estimated 1.8[6] times the mass of the Sun and has expanded to 10 times the Sun's radius.[2] It is radiating 53[2] times the solar luminosity from its photosphere at an effective temperature of 4,660 K.[6]
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.[10] 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.[11][12]
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.[13] Consequently, the Chinese name for θ Ceti itself is 天倉三 (Tiān Cāng sān, English: the Third Star of Square Celestial Granary).[14]