The KOI-1257 system contains 1 exoplanet. It is located 2139.58 light years away from the solar system.
| Mass | 0.99 solar masses |
| Radius | 1.13 solar radiae |
| Temperature | 5520 kelvin |
| Stellar Metallicity | 0.27 decimal exponent |
| Age | 9.3 billion years |
At more than 50 Earth masses, KOI-1257 b is a gas giant, a planet whose mass is mostly made up of hydrogen and helium, like Jupiter and Saturn.
| Mass | 460.830 Earth masses |
| Density | 2.100 grams per cubic centimeter |
| Radius | 10.540 Earth radiae |
| Semi-major Axis | 0.382 AU |
| Eccentricity | 0.772 |
| Orbital Period | 86.648 days |
| Discovery Method | Transit |
| Discovery Facility | Kepler |
| Discovery Telescope | 0.95 m Kepler Telescope |
| Discovery Instrument | Kepler CCD Array |
| Discovery Date | 2014-06 |
| Reference | Santerne et al. 2014 |