The tau Cet system contains 4 exoplanets. It is located 11.75 light years away from the solar system.
| Mass | 0.78 solar masses |
| Radius | 0.83 solar radiae |
| Temperature | 5310 kelvin |
| Stellar Metallicity | -0.52 decimal exponent |
| Age | 12.12 billion years |
At 3.934 Earth masses, tau Cet e is a so called Super Earth. Super Earths could be terrestrial worlds like Earth, but they could also be ocean worlds or terrestrial worlds wrapped in a substantial atmosphere, in which case some refer to them as Mini Neptunes. tau Cet e orbits within the habitable zone of its parent star and could, potentially, be a habitable planet with stable bodies of liquid water on its surface, like Earth.
| Mass | 3.930 Earth masses |
| Density | 3.640 grams per cubic centimeter |
| Radius | 1.810 Earth radiae |
| Semi-major Axis | 0.538 AU |
| Eccentricity | 0.18 |
| Orbital Period | 162.870 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | Multiple Observatories |
| Discovery Telescope | Multiple Telescopes |
| Discovery Instrument | Multiple Instruments |
| Discovery Date | 2017-10 |
| Reference | Feng et al. 2017 |
At 3.934 Earth masses, tau Cet f is a so called Super Earth. Super Earths could be terrestrial worlds like Earth, but they could also be ocean worlds or terrestrial worlds wrapped in a substantial atmosphere, in which case some refer to them as Mini Neptunes. With a mass below 5 Earth masses, and a semi-major axis of 1.334 astronomical units, which is outside the habitable zone of tau Cet, tau Cet f is likely an icy world.
| Mass | 3.930 Earth masses |
| Density | 3.640 grams per cubic centimeter |
| Radius | 1.810 Earth radiae |
| Semi-major Axis | 1.334 AU |
| Eccentricity | 0.16 |
| Orbital Period | 636.130 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | Multiple Observatories |
| Discovery Telescope | Multiple Telescopes |
| Discovery Instrument | Multiple Instruments |
| Discovery Date | 2017-10 |
| Reference | Feng et al. 2017 |
At 1.752 Earth masses, tau Cet g is a so called Super Earth. Super Earths could be terrestrial worlds like Earth, but they could also be ocean worlds or terrestrial worlds wrapped in a substantial atmosphere, in which case some refer to them as Mini Neptunes.
| Mass | 1.750 Earth masses |
| Density | 5.850 grams per cubic centimeter |
| Radius | 1.180 Earth radiae |
| Semi-major Axis | 0.133 AU |
| Eccentricity | 0.06 |
| Orbital Period | 20.000 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | Multiple Observatories |
| Discovery Telescope | Multiple Telescopes |
| Discovery Instrument | Multiple Instruments |
| Discovery Date | 2017-10 |
| Reference | Feng et al. 2017 |
At 1.832 Earth masses, tau Cet h is a so called Super Earth. Super Earths could be terrestrial worlds like Earth, but they could also be ocean worlds or terrestrial worlds wrapped in a substantial atmosphere, in which case some refer to them as Mini Neptunes.
| Mass | 1.830 Earth masses |
| Density | 5.970 grams per cubic centimeter |
| Radius | 1.190 Earth radiae |
| Semi-major Axis | 0.243 AU |
| Eccentricity | 0.23 |
| Orbital Period | 49.410 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | Multiple Observatories |
| Discovery Telescope | Multiple Telescopes |
| Discovery Instrument | Multiple Instruments |
| Discovery Date | 2017-10 |
| Reference | Feng et al. 2017 |