Tau Ceti (τ Cet)
Tau Ceti (τ Cet) is a star in the constellation Cetus, magnitude 3.5.
The nearest lone Sun-like star — older than the Sun, and a favourite of SETI and science fiction.
Of all the Sun’s near neighbours, Tau Ceti is the closest single star of the Sun’s own class G. It is close kin, but not a twin: it has about 78% of the Sun’s mass and 79% of its radius, gives out just over half as much light, and holds only about a third as much iron. That shortage hints at age — most estimates put it near 9 billion years old, against the Sun’s 4.6.
A steady, Sun-like star made an obvious target in the hunt for life. In 1960 Frank Drake pointed a radio dish at Green Bank, West Virginia, towards Tau Ceti for Project Ozma, the first modern search for alien signals. Several candidate planets have been proposed since, but none has been confirmed beyond doubt — and with more than ten times as much dust as the Solar System, any planet there would suffer far more impacts than Earth.
Fiction has been kinder. Ursula K. Le Guin set her novel The Dispossessed on a pair of worlds in the Tau Ceti system.
Tau Ceti (τ Cet) is 11.9 light-years away: the light we see from it set off in 2014, 7 years before the James Webb Space Telescope was launched.
Did you know?
- Our Sun, seen from there. From a planet of Tau Ceti, the Sun would be an ordinary 2.6-magnitude star in the constellation Boötes.
- Coming closer. Tau Ceti is heading our way: in about 43,000 years it will pass closest to the Sun, before moving off again.
- The third ostrich. A 17th-century star calendar from Cairo called it ‘the third of the ostriches’, one of five stars of Cetus seen as hen ostriches.
A yellowish 3.5-magnitude star in the body of Cetus, about six degrees south-south-west of Baten Kaitos (Zeta Ceti). It looks plain, but its light is close to the Sun’s: compare its soft yellow with orange Diphda to the west.
When and where to see it
It is best placed in the evening sky around November, when it crosses the meridian at about 10 pm local time (around midnight in October). It can be seen from everywhere south of 74°N and never sets south of 74°S.
At its highest it stands 24° up from 50°N, 39° up from 35°N, 74° up from the equator, 71° up from 35°S.
Facts
- Type
- Star
- Constellation
- Cetus
- Designations
- τ Cet, 52 Cet, HR 509, HD 10700, HIP 8102
- Magnitude
- 3.5
- Position
- RA 1h 44.1m, Dec −15° 56′ (J2000)
- Spectral type
- G8V
- Colour
- yellow (B−V 0.72)
- Distance
- 11.9 light-years
- Discovered
- Known since antiquity
Open AstroPilot to see when Tau Ceti (τ Cet) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view.