The Kepler-166 system contains 3 exoplanets. It is located 1968.45 light years away from the solar system.
| Mass | 0.88 solar masses |
| Radius | 0.74 solar radiae |
| Temperature | 5413 kelvin |
| Stellar Metallicity | -0.03 decimal exponent |
| Age | 0.8 billion years |
At more than 10 Earth masses, Kepler-166 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 | 5.770 Earth masses |
| Density | 2.710 grams per cubic centimeter |
| Radius | 2.270 Earth radiae |
| Semi-major Axis | 0.072 AU |
| Eccentricity | 0 |
| Orbital Period | 7.650 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 |
At more than 10 Earth masses, Kepler-166 c 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 | 6.260 Earth masses |
| Density | 2.550 grams per cubic centimeter |
| Radius | 2.380 Earth radiae |
| Semi-major Axis | 0.195 AU |
| Eccentricity | 0 |
| Orbital Period | 34.260 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 |
At 3.657 Earth masses, Kepler-166 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 | 3.640 Earth masses |
| Density | 3.860 grams per cubic centimeter |
| Radius | 1.730 Earth radiae |
| Semi-major Axis | 0.0246 AU |
| Eccentricity | 0 |
| Orbital Period | 1.554 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2016-05 |
| Reference | Morton et al. 2016 |