The 81 Cet system contains 1 exoplanet. It is located 330.27 light years away from the solar system.
| Mass | 2.4 solar masses |
| Radius | 11 solar radiae |
| Temperature | 4785 kelvin |
| Stellar Metallicity | -0.06 decimal exponent |
| Age | - billion years |
At more than 50 Earth masses, 81 Cet b is a gas giant, a planet whose mass is mostly made up of hydrogen and helium, like Jupiter and Saturn.
| Mass | 1684.400 Earth masses |
| Density | 4.410 grams per cubic centimeter |
| Radius | 12.800 Earth radiae |
| Semi-major Axis | 2.5 AU |
| Eccentricity | 0.206 |
| Orbital Period | 952.700 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | Okayama Astrophysical Observatory |
| Discovery Telescope | 1.88 m Telescope |
| Discovery Instrument | HIDES Echelle Spectrograph |
| Discovery Date | 2008-12 |
| Reference | Sato et al. 2008 |