The Kepler-9 system contains 3 exoplanets. It is located 2049.10 light years away from the solar system.
| Mass | 1.02 solar masses |
| Radius | 0.96 solar radiae |
| Temperature | 5774 kelvin |
| Stellar Metallicity | 0.05 decimal exponent |
| Age | 2 billion years |
At more than 10 Earth masses, Kepler-9 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 | 43.400 Earth masses |
| Density | 0.420 grams per cubic centimeter |
| Radius | 8.290 Earth radiae |
| Semi-major Axis | 0.143 AU |
| Eccentricity | 0.0609 |
| Orbital Period | 19.239 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2010-10 |
| Reference | Holman et al. 2010 |
At more than 10 Earth masses, Kepler-9 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 | 29.900 Earth masses |
| Density | 0.310 grams per cubic centimeter |
| Radius | 8.080 Earth radiae |
| Semi-major Axis | 0.227 AU |
| Eccentricity | 0.06691 |
| Orbital Period | 38.985 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2010-10 |
| Reference | Holman et al. 2010 |
At 3.339 Earth masses, Kepler-9 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 | 3.330 Earth masses |
| Density | 4.150 grams per cubic centimeter |
| Radius | 1.640 Earth radiae |
| Semi-major Axis | 0.0273 AU |
| Eccentricity | 0 |
| Orbital Period | 1.593 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2011-01 |
| Reference | Torres et al. 2011 |