Kepler-111 c
Kepler-111 c is a cold gas giant orbiting Kepler-111 in the constellation Cygnus. It lies about 2,144 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-111 c?
Kepler-111 c has a radius of 7.08 times that of Earth, or 0.63 times the radius of Jupiter. Its mass is 222 times that of Earth, giving it a density of 3.42 g/cm³ — between that of rocky and gaseous planets.
Is Kepler-111 c in the Habitable Zone?
Kepler-111 c orbits inside the inner edge of the habitable zone of Kepler-111. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-111: 0.912–2.139 AU (conservative: 1.155–2.028 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-111 c
The equilibrium temperature of Kepler-111 c is about 352 K (79 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 2.48 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-111 c — one full orbit around Kepler-111 — lasts 224.8 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.751 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.18).
How Was Kepler-111 c Discovered?
Kepler-111 c was discovered in 2014 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-111 c?
Kepler-111 c is 2,143.6 light-years (657.2 parsecs) from Earth. Light arriving here tonight left the planet about 2,144 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 37,727,360 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-111 c scores 0.37, ranking #610 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-111
Kepler-111
- Surface temperature
- 5,952 K (Sun: 5,772 K)
- Radius
- 1.16 R☉
The Kepler-111 Planetary System
Kepler-111 c is one of 2 known planets in the Kepler-111 system. Its siblings:
- Kepler-111 b (Super Earth)
Kepler-111 c — Complete Data
| Radius | 7.084 Earth radii (0.632 Jupiter radii) |
|---|---|
| Mass | 222.48 Earth masses (0.700 Jupiter masses) |
| Density | 3.42 g/cm³ (Earth: 5.51) |
| Orbital period | 224.78 days |
| Orbital distance | 0.751 AU |
| Eccentricity | 0.176 |
| Equilibrium temperature | 352 K (79 °C) |
| Stellar irradiation | 2.48× Earth |
| Earth Similarity Index | 0.37 |
| Distance from Earth | 2,143.6 light-years (657.2 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2024-09-13. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-111 c
Is Kepler-111 c habitable?
No — Kepler-111 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-111 c?
Kepler-111 c is about 2,144 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 37,727,360 years to get there.
How big is Kepler-111 c compared to Earth?
Kepler-111 c has 7.08 times the radius of Earth and about 222 times its mass.
How long is a year on Kepler-111 c?
One orbit around Kepler-111 takes 224.8 Earth days.
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