  | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 00m 00.30916s[1] |
| Declination | −21° 04′ 40.1946″[1] |
| Apparent magnitude (V) | 3.95[2] |
| Characteristics | |
| Evolutionary stage | asymptotic giant branch[3] |
| Spectral type | M0III[4] |
| U−Bcolor index | +1.90[2] |
| B−Vcolor index | +1.57[2] |
| Astrometry | |
| Radial velocity (Rv) | +18.00±0.70[5] km/s |
| Proper motion (μ) | RA: +134.92[1]mas/yr Dec.: −24.59[1]mas/yr |
| Parallax (π) | 11.14±0.18 mas[1] |
| Distance | 293 ± 5 ly (90 ± 1 pc) |
| Absolute magnitude (MV) | −0.77[6] |
| Details[7] | |
| Mass | 1.26±0.13 M☉ |
| Radius | 53.56±11.80 R☉ |
| Luminosity | 549.6±226.8 L☉ |
| Surface gravity (log g) | 1.15±0.18 cgs |
| Temperature | 3,822±148 K |
| Metallicity [Fe/H] | −0.06±0.10 dex |
| Age | 6.97±2.77 Gyr |
| Other designations | |
| υ Cet,59 Cet,BD−21° 358,FK5 71,HD 12274,HIP 9347,HR 585,SAO 167471.[8] | |
| Database references | |
| SIMBAD | data |
Upsilon Ceti,Latinized from υ Ceti, is a solitary[9]star in theequatorialconstellation ofCetus. It is visible to the naked eye with anapparent visual magnitude of 3.95.[2] Based upon an annualparallax shift of 11.14 mas,[1] it is located about 293 light years from theSun.
This star was designated Upsilon Ceti byBayer and 59 Ceti byFlamsteed. Flamsteed also gave it the designation Upsilon2 Ceti to distinguish it from56 Ceti, which he called Upsilon1. Flamsteed's superscripted designations, however, are not in general use today.[10]
For ancient Arabic astronomers, this star withη Cet (Deneb Algenubi),θ Cet (Thanih al Naamat),τ Cet (Durre Menthor) andζ Cet (Baten Kaitos), formedAl Naʽāmāt (النعامات), the Hen Ostriches[11] InChinese,鈇鑕 (Fū Zhì), meaningSickle, refers to an asterism consisting of υ Ceti,48 Ceti and56 Ceti.[12] Consequently, theChinese name for υ Ceti itself is鈇鑕四 (Fū Zhì sì, English:the Fourth Star of Sickle.)[13]
Upsilon Ceti is anevolvedred giant star with astellar classification of M0III and is listed as a standard for that class.[4] The star has previously been classified as K5/M0III,[14] an interesting example of one of the "gaps" in theMorgan-Keenan classification system, with K6-9 often not used for giant stars or used only to indicate a fraction of the way between K5 and M0.[4]
There is an 84% chance that it is on thered giant branch, or 16% to be on thehorizontal branch. Stellar models based on the red giant branch status yield an estimated mass of around 126% of theSun's mass and 54 times theradius of the Sun. This model indicates the star radiates around 550 times thesolar luminosity from itsouter atmosphere at aneffective temperature of 3,822 K.[7]
