Kepler-864 c
Kepler-864 c is a lava world orbiting Kepler-864 in the constellation Lyra. It lies about 6,598 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is Kepler-864 c?
Kepler-864 c has a radius of 1.62 times that of Earth.
Is Kepler-864 c in the Habitable Zone?
Kepler-864 c orbits inside the inner edge of the habitable zone of Kepler-864. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-864: 0.745–1.757 AU (conservative: 0.944–1.666 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-864 c
The equilibrium temperature of Kepler-864 c is about 1,532 K (1,259 °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. It receives 1,305 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-864 c — one full orbit around Kepler-864 — lasts 2.42 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.038 AU — closer to its star than Mercury is to the Sun.
How Was Kepler-864 c Discovered?
Kepler-864 c was discovered in 2023 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-864 c?
Kepler-864 c is 6,597.8 light-years (2,022.9 parsecs) from Earth. Light arriving here tonight left the planet about 6,598 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 116,121,280 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-864 c scores 0.27, ranking #2,441 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-864
Kepler-864
- Surface temperature
- 5,754 K (Sun: 5,772 K)
- Mass
- 1.00 M☉
- Radius
- 1.00 R☉
- Age
- 4.7 billion years (Sun: 4.6)
The Kepler-864 Planetary System
Kepler-864 c is one of 2 known planets in the Kepler-864 system. Its siblings:
- Kepler-864 b (Mini Neptune)
Kepler-864 c — Complete Data
| Radius | 1.620 Earth radii (0.145 Jupiter radii) |
|---|---|
| Orbital period | 2.42 days |
| Orbital distance | 0.038 AU |
| Equilibrium temperature | 1,532 K (1,259 °C) |
| Stellar irradiation | 1,305.04× Earth |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 6,597.8 light-years (2,022.9 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2017-05-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-864 c
Is Kepler-864 c habitable?
No — Kepler-864 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-864 c?
Kepler-864 c is about 6,598 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 116,121,280 years to get there.
How big is Kepler-864 c compared to Earth?
Kepler-864 c has 1.62 times the radius of Earth.
How long is a year on Kepler-864 c?
One orbit around Kepler-864 takes 2.4 Earth days — short enough that 151 of its years would fit into one Earth year.
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