Tau Ceti
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus |
| Pronunciation | /ˌtaʊ ˈsiːtaɪ/ |
| Right ascension | 01h 44m 04.083s |
| Declination | −15° 56′ 14.93″ |
| Apparent magnitude (V) | 3.50±0.01 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G8V |
| U−B color index | +0.21 |
| B−V color index | +0.72 |
| Astrometry | |
| Radial velocity (Rv) | −16.68±0.05 km/s |
| Proper motion (μ) | RA: −1721.728 mas/yr Dec.: +854.963 mas/yr |
| Parallax (π) | 273.8097±0.1701 mas |
| Distance | 11.912 ± 0.007 ly (3.652 ± 0.002 pc) |
| Absolute magnitude (MV) | 5.69±0.01 |
| Absolute bolometric magnitude (Mbol) | 5.52±0.02 |
| Details | |
| Mass | 0.800±0.008 M☉ |
| Radius | 0.793±0.004 R☉ |
| Luminosity | 0.488±0.010 L☉ |
| Luminosity (visual, LV) | 0.45 L☉ |
| Surface gravity (log g) | 4.48±0.05 cgs |
| Temperature | 5,320±40 K |
| Metallicity | 28±3% Sun |
| Metallicity [Fe/H] | −0.55±0.05 dex |
| Rotation | 46±4 d |
| Rotational velocity (v sin i) | 0.1±0.1 km/s |
| Age | 8–10 Gyr |
| Other designations | |
| τ Cet, 52 Cet, BD−16°295, FK5 59, GJ 71, HD 10700, HIP 8102, HR 509, SAO 147986, LFT 159, LHS 146, LTT 935 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
Tau Ceti, Latinized from τ Ceti, is a single star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under 12 light-years (3.7 parsecs) from the Solar System, it is a relatively nearby star and the closest solitary G-class star. The star appears stable, with little stellar variation, and is metal-deficient (low in elements other than hydrogen and helium) relative to the Sun.
It can be seen with the unaided eye with an apparent magnitude of 3.5. As seen from Tau Ceti, the Sun would be in the northern hemisphere constellation Boötes with an apparent magnitude of about 2.6.
Observations have detected more than ten times as much dust surrounding Tau Ceti as is present in the Solar System. Tau Ceti has been an object of interest for exoplanet searches, and a number of candidate planets have been proposed, but as of 2025 there remains no unambiguous evidence of planets. Because of its debris disk, any planet orbiting Tau Ceti would face far more impact events than present day Earth. Despite this hurdle to habitability, its solar analog (Sun-like) characteristics have led to widespread interest in the star. Given its stability, similarity and relative proximity to the Sun, Tau Ceti is consistently listed as a target for the search for extraterrestrial intelligence (SETI).