Tau Ceti (t Cet, t 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, and is the closest solitary G-class star. The star appears stable, with little stellar variation, and is metal-deficient.