| Discovery | |
|---|---|
| Discovery site | Kepler Space Observatory |
| Discovery date | 2014 |
| Transit | |
| Orbital characteristics | |
| ~0.209 AU | |
| Eccentricity | null[1] |
| 33.006[1] d | |
| Inclination | null[1] |
| Star | Kepler-277 |
| Physical characteristics | |
| 3.36 +0.83 −0.72[1] R🜨 | |
| Mass | 64.2 +18.1 −15.7[1][2] ME |
Mean density | 9.33+15.33 −5.69 g cm−3 |
| 5.69+6.12 −2.93 g | |
| Temperature | 745 K (472 °C; 881 °F)[3] |
Kepler-277c (also known by its Kepler Objects of Interest designation KOI-1215.02) is the third most massive and second-largest rocky planet ever discovered, with a mass about 64 times that of Earth. Discovered in 2014 by the Kepler Space Telescope, Kepler-277c is a Neptune-sized exoplanet with a very high mass and density for an object of its radius, suggesting a composition made mainly of rock with some amounts of water. Along with its sister planet, Kepler-277b, the planet's mass was determined using transit-timing variations (TTVs).