Kepler-170 c
Kepler-170 c is a mini-Neptune orbiting Kepler-170 in the constellation Lyra. It lies about 2,409 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-170 c?
Kepler-170 c has a radius of 2.86 times that of Earth.
Is Kepler-170 c in the Habitable Zone?
Kepler-170 c orbits inside the inner edge of the habitable zone of Kepler-170. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-170: 0.755–1.783 AU (conservative: 0.956–1.691 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-170 c — one full orbit around Kepler-170 — lasts 16.7 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.131 AU — closer to its star than Mercury is to the Sun.
How Was Kepler-170 c Discovered?
Kepler-170 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-170 c?
Kepler-170 c is 2,409.2 light-years (738.7 parsecs) from Earth. Light arriving here tonight left the planet about 2,409 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 42,401,920 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-170 c scores 0.24, ranking #3,330 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-170
Kepler-170
- Surface temperature
- 5,679 K (Sun: 5,772 K)
- Radius
- 1.03 R☉
The Kepler-170 Planetary System
Kepler-170 c is one of 2 known planets in the Kepler-170 system. Its siblings:
- Kepler-170 b (Sub Neptune)
Kepler-170 c — Complete Data
| Radius | 2.860 Earth radii (0.255 Jupiter radii) |
|---|---|
| Orbital period | 16.67 days |
| Orbital distance | 0.131 AU |
| Earth Similarity Index | 0.24 |
| Distance from Earth | 2,409.2 light-years (738.7 parsecs) |
| Constellation | Lyra |
| 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-170 c
Is Kepler-170 c habitable?
No — Kepler-170 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-170 c?
Kepler-170 c is about 2,409 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 42,401,920 years to get there.
How big is Kepler-170 c compared to Earth?
Kepler-170 c has 2.86 times the radius of Earth.
How long is a year on Kepler-170 c?
One orbit around Kepler-170 takes 16.7 Earth days — short enough that 22 of its years would fit into one Earth year.
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