Kepler-101 c
Kepler-101 c is a terrestrial planet orbiting the G3 IV star Kepler-101 in the constellation Draco. It lies about 3,027 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-101 c?
Kepler-101 c has a radius of 1.25 times that of Earth. Its mass is 3.8 times that of Earth, giving it a density of 10.50 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is Kepler-101 c in the Habitable Zone?
Kepler-101 c orbits inside the inner edge of the habitable zone of Kepler-101. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-101: 1.134–2.679 AU (conservative: 1.436–2.540 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 ›
Temperature on Kepler-101 c
The equilibrium temperature of Kepler-101 c is about 1,413 K (1,140 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on Kepler-101 c — one full orbit around Kepler-101 — lasts 6.03 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.068 AU — closer to its star than Mercury is to the Sun.
How Was Kepler-101 c Discovered?
Kepler-101 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-101 c?
Kepler-101 c is 3,026.7 light-years (928.0 parsecs) from Earth. Light arriving here tonight left the planet about 3,027 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 53,269,920 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-101 c scores 0.29, ranking #1,796 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-101
Kepler-101
- Spectral type
- G3 IV
- Surface temperature
- 5,667 K (Sun: 5,772 K)
- Mass
- 1.17 M☉
- Radius
- 1.56 R☉
- Age
- 5.9 billion years (Sun: 4.6)
The Kepler-101 Planetary System
Kepler-101 c is one of 2 known planets in the Kepler-101 system. Its siblings:
- Kepler-101 b (Neptune-like)
Kepler-101 c — Complete Data
| Radius | 1.250 Earth radii (0.112 Jupiter radii) |
|---|---|
| Mass | 3.78 Earth masses (0.010 Jupiter masses) |
| Density | 10.50 g/cm³ (Earth: 5.51) |
| Orbital period | 6.03 days |
| Orbital distance | 0.068 AU |
| Equilibrium temperature | 1,413 K (1,140 °C) |
| Earth Similarity Index | 0.29 |
| Distance from Earth | 3,026.7 light-years (928.0 parsecs) |
| Constellation | Draco |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-09-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-101 c
Is Kepler-101 c habitable?
No — Kepler-101 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-101 c?
Kepler-101 c is about 3,027 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 53,269,920 years to get there.
How big is Kepler-101 c compared to Earth?
Kepler-101 c has 1.25 times the radius of Earth and about 3.8 times its mass.
How long is a year on Kepler-101 c?
One orbit around Kepler-101 takes 6.0 Earth days — short enough that 61 of its years would fit into one Earth year.
Explore Kepler-101 c in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
