| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 21m 46.27529s[2] |
| Declination | −20° 03′ 28.9098″[2] |
| Apparent magnitude (V) | 5.61[3](5.0 - 6.9)[4] |
| Characteristics | |
| Spectral type | M5-6Se[5] |
| B−Vcolor index | 1.58±0.03[3] |
| Variable type | SRc[6] |
| Astrometry | |
| Radial velocity (Rv) | +28.9±0.9[7] km/s |
| Proper motion (μ) | RA: +59.665[2]mas/yr Dec.: −10.229[2]mas/yr |
| Parallax (π) | 3.70±0.47 mas[8] |
| Distance | approx. 900 ly (approx. 270 pc) |
| Absolute magnitude (MV) | −1.51[3] |
| Details[6] | |
| Mass | 3.0±0.3 M☉ |
| Radius | 275±34 R☉ |
| Luminosity | 8,128+2,587 −1,962 L☉ |
| Surface gravity (log g) | 0.01±0.11 cgs |
| Temperature | 3,396+103 −100 K |
| Metallicity [Fe/H] | 0.0 dex |
| Other designations | |
| T Cet,BD−20°50,HD 1760,HIP 1728,HR 85,SAO 166210[9] | |
| Database references | |
| SIMBAD | data |
T Ceti is asemiregularvariable star located in the equatorialconstellation ofCetus. It varies betweenmagnitudes 5.0 and 6.9 over 159.3 days, making it faintly visible to thenaked eye except when near minimum brightness.[4] Thestellar parallax shift measured byHipparcos is3.7 mas,[8] which yields a distance estimate of roughly 900 light years. It is moving further from the Earth with a heliocentricradial velocity of +29 km/s.[7]
Seth Carlo Chandler discovered that the star is a variable star, during the northern hemisphere winter of 1881-1882.[10] It was listed with itsvariable star designation, T Ceti, inAnnie Jump Cannon's 1907 workSecond Catalog of Variable Stars.[11]
This is anMS-type star on theasymptotic giant branch with a spectral type of M5-6Se.[5] (The 'e' notation indicates the presence ofemission lines in thespectrum). The star is losing mass at the rate of8.2×10−8 M☉ y−1,[12] and it is surrounded by a circumstellar dust shell consisting of crystallized, mostly iron-rich silicates.[13]
T Ceti has an estimated three times themass of the Sun and has expanded to 275 times theSun's radius. It is radiating 8,128 times theSun's luminosity from its enlargedphotosphere at aneffective temperature of 3,396 K.[6]
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