The Kepler-81 system contains 3 exoplanets. It is located 1135.97 light years away from the solar system.
| Mass | 0.64 solar masses |
| Radius | 0.59 solar radiae |
| Temperature | 4385 kelvin |
| Stellar Metallicity | -0.18 decimal exponent |
| Age | 3.63 billion years |
At more than 10 Earth masses, Kepler-81 b is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune.
| Mass | 17.200 Earth masses |
| Density | 6.670 grams per cubic centimeter |
| Radius | 2.420 Earth radiae |
| Semi-major Axis | 0.0522 AU |
| Eccentricity | 0 |
| Orbital Period | 5.955 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2013-10 |
| Reference | Xie 2013 |
With a mass below 5 Earth masses, a density of 1.77, and a semi-major axis of 0.08347 astronomical units, Kepler-81 c could, potentially, be an ocean world - a planet with no dry land.
| Mass | 4.300 Earth masses |
| Density | 1.770 grams per cubic centimeter |
| Radius | 2.370 Earth radiae |
| Semi-major Axis | 0.08347 AU |
| Eccentricity | 0 |
| Orbital Period | 12.040 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2013-10 |
| Reference | Xie 2013 |
At 1.927 Earth masses, Kepler-81 d 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 | 1.920 Earth masses |
| Density | 5.960 grams per cubic centimeter |
| Radius | 1.210 Earth radiae |
| Semi-major Axis | 0.128 AU |
| Eccentricity | 0 |
| Orbital Period | 20.838 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2014-03 |
| Reference | Rowe et al. 2014 |