Tau Ceti (τ Cet, τ Ceti) is a 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 from the Solar System, it is a relatively nearby star. Tau Ceti is metal-deficient and so is thought to be less likely to host rocky planets. Observations have detected more than ten times as much dust surrounding Tau Ceti as is present in the Solar System. The star appears stable, with little stellar variation.
Astrometric or radial velocity measurements have not yet detected companions around Tau Ceti, but given current search refinement, this only excludes substellar companions such as large brown dwarfs. Because of its debris disk, any planet orbiting Tau Ceti would face far more impact events than the 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 Extra-Terrestrial Intelligence (SETI), and it appears in some science fiction literature.
Tau Ceti does not have a widely-recognized traditional name. It can be seen with the unaided eye as a faint third-magnitude star. As seen from Tau Ceti, the Sun would be a third-magnitude star in the constellation Boötes.