Kepler-266 c
Kepler-266 c is a sub-Neptune orbiting Kepler-266 in the constellation Cygnus. It lies about 4,471 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-266 c?
Kepler-266 c has a radius of 3.89 times that of Earth.
Is Kepler-266 c in the Habitable Zone?
Kepler-266 c orbits inside the inner edge of the habitable zone of Kepler-266. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-266: 0.795–1.868 AU (conservative: 1.007–1.771 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-266 c — one full orbit around Kepler-266 — lasts 107.7 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.457 AU — comparable to the inner Solar System.
How Was Kepler-266 c Discovered?
Kepler-266 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-266 c?
Kepler-266 c is 4,470.9 light-years (1,370.8 parsecs) from Earth. Light arriving here tonight left the planet about 4,471 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 78,687,840 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-266 c scores 0.37, ranking #609 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-266
Kepler-266
- Surface temperature
- 5,885 K (Sun: 5,772 K)
- Radius
- 1.03 R☉
The Kepler-266 Planetary System
Kepler-266 c is one of 2 known planets in the Kepler-266 system. Its siblings:
- Kepler-266 b (Mini Neptune)
Kepler-266 c — Complete Data
| Radius | 3.890 Earth radii (0.347 Jupiter radii) |
|---|---|
| Orbital period | 107.72 days |
| Orbital distance | 0.457 AU |
| Earth Similarity Index | 0.37 |
| Distance from Earth | 4,470.9 light-years (1,370.8 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-266 c
Is Kepler-266 c habitable?
No — Kepler-266 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-266 c?
Kepler-266 c is about 4,471 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 78,687,840 years to get there.
How big is Kepler-266 c compared to Earth?
Kepler-266 c has 3.89 times the radius of Earth.
How long is a year on Kepler-266 c?
One orbit around Kepler-266 takes 107.7 Earth days.
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