The Kepler-257 system contains 3 exoplanets. It is located 2544.85 light years away from the solar system.
| Mass | 0.85 solar masses |
| Radius | 1.04 solar radiae |
| Temperature | 5180 kelvin |
| Stellar Metallicity | 0.04 decimal exponent |
| Age | 14 billion years |
At more than 10 Earth masses, Kepler-257 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 | 7.320 Earth masses |
| Density | 2.260 grams per cubic centimeter |
| Radius | 2.610 Earth radiae |
| Semi-major Axis | 0.034 AU |
| Eccentricity | 0 |
| Orbital Period | 2.383 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-257 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 | 25.200 Earth masses |
| Density | 0.875 grams per cubic centimeter |
| Radius | 5.410 Earth radiae |
| Semi-major Axis | 0.066 AU |
| Eccentricity | 0 |
| Orbital Period | 6.581 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-257 d 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 | 21.700 Earth masses |
| Density | 0.983 grams per cubic centimeter |
| Radius | 4.950 Earth radiae |
| Semi-major Axis | 0.16 AU |
| Eccentricity | 0 |
| Orbital Period | 24.665 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 |