Tau Ceti (τ Cet, τ Ceti) is a star in the constellation Cetus. It can be seen with the unaided eye as a third-magnitude star.
It has a spectrum similar to the Sun, but is only 78% of the Sun's mass. It is just under 12 light-years from the Solar System, a relatively nearby star. It is the closest solitary G-class star. The star appears stable, and is "metal-deficient" because (like the Sun) it is mostly made of hydrogen and helium.
There is more than ten times as much dust surrounding Tau Ceti as in the Solar System. There are probably five planets orbiting Tau Ceti, two in the habitable zone. Because of its debris disk, any planet orbiting Tau Ceti would get far more impact events than Earth. Despite this, its Sun-like characteristics have led to widespread interest in the star. Tau Ceti is consistently listed as a target for the Search for Extra-Terrestrial Intelligence (SETI), and it appears in some science fiction literature.