Kepler-57 c
Kepler-57 c is a super-Earth orbiting Kepler-57 in the constellation Cygnus. It lies about 2,101 light-years from Earth and was discovered in 2012 using the transit method.
How Big Is Kepler-57 c?
Kepler-57 c has a radius of 2.20 times that of Earth. Its mass is 6.9 times that of Earth, giving it a density of 3.53 g/cm³ — between that of rocky and gaseous planets.
Is Kepler-57 c in the Habitable Zone?
The position of Kepler-57 c relative to the habitable zone of Kepler-57 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-57: 0.517–1.240 AU (conservative: 0.654–1.176 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on Kepler-57 c — one full orbit around Kepler-57 — lasts 11.6 Earth days, shorter than Mercury's 88-day year. Its orbit is mildly elliptical (eccentricity 0.07).
How Was Kepler-57 c Discovered?
Kepler-57 c was discovered in 2012 using the transit method, with observations from Kepler.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is Kepler-57 c?
Kepler-57 c is 2,100.9 light-years (644.1 parsecs) from Earth. Light arriving here tonight left the planet about 2,101 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 36,975,840 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. Kepler-57 c scores 0.30, ranking #1,263 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-57
Kepler-57
- Surface temperature
- 5,188 K (Sun: 5,772 K)
- Mass
- 0.86 M☉
- Radius
- 0.83 R☉
The Kepler-57 Planetary System
Kepler-57 c is one of 2 known planets in the Kepler-57 system. Its siblings:
- Kepler-57 b (Super Earth)
Kepler-57 c — Complete Data
| Radius | 2.196 Earth radii (0.196 Jupiter radii) |
|---|---|
| Mass | 6.86 Earth masses (0.022 Jupiter masses) |
| Density | 3.53 g/cm³ (Earth: 5.51) |
| Orbital period | 11.60 days |
| Eccentricity | 0.073 |
| Earth Similarity Index | 0.30 |
| Distance from Earth | 2,100.9 light-years (644.1 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2012 |
Data: NASA Exoplanet Archive, last updated 2024-06-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-57 c
Is Kepler-57 c habitable?
Kepler-57 c is not known to orbit within the habitable zone of Kepler-57, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is Kepler-57 c?
Kepler-57 c is about 2,101 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 36,975,840 years to get there.
How big is Kepler-57 c compared to Earth?
Kepler-57 c has 2.20 times the radius of Earth and about 6.9 times its mass.
How long is a year on Kepler-57 c?
One orbit around Kepler-57 takes 11.6 Earth days — short enough that 31 of its years would fit into one Earth year.
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