K2-36 b
K2-36 b is a super-Earth orbiting K2-36 in the constellation Leo. It lies about 358 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is K2-36 b?
K2-36 b has a radius of 1.43 times that of Earth. Its mass is 4.3 times that of Earth, giving it a density of 8.00 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is K2-36 b in the Habitable Zone?
K2-36 b orbits inside the inner edge of the habitable zone of K2-36. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-36: 0.409–0.992 AU (conservative: 0.518–0.940 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-36 b
The equilibrium temperature of K2-36 b is about 1,328 K (1,055 °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 519 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on K2-36 b — one full orbit around K2-36 — lasts just 34.1 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.023 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.09).
How Was K2-36 b Discovered?
K2-36 b was discovered in 2016 using the transit method, with observations from K2.
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 K2-36 b?
K2-36 b is 358.0 light-years (109.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1668. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 6,300,800 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. K2-36 b scores 0.28, ranking #2,092 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-36
K2-36
- Surface temperature
- 4,916 K (Sun: 5,772 K)
- Mass
- 0.79 M☉
- Radius
- 0.72 R☉
The K2-36 Planetary System
K2-36 b is one of 2 known planets in the K2-36 system. Its siblings:
- K2-36 c (Puffy Planet)
K2-36 b — Complete Data
| Radius | 1.430 Earth radii (0.128 Jupiter radii) |
|---|---|
| Mass | 4.30 Earth masses (0.014 Jupiter masses) |
| Density | 8.00 g/cm³ (Earth: 5.51) |
| Orbital period | 1.42 days |
| Orbital distance | 0.023 AU |
| Eccentricity | 0.093 |
| Equilibrium temperature | 1,328 K (1,055 °C) |
| Stellar irradiation | 519.00× Earth |
| Earth Similarity Index | 0.28 |
| Distance from Earth | 358.0 light-years (109.7 parsecs) |
| Constellation | Leo |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2023-04-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-36 b
Is K2-36 b habitable?
No — K2-36 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-36 b?
K2-36 b is about 358 light-years from Earth in the constellation Leo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 6,300,800 years to get there.
How big is K2-36 b compared to Earth?
K2-36 b has 1.43 times the radius of Earth and about 4.3 times its mass.
How long is a year on K2-36 b?
One orbit around K2-36 takes 1.4 Earth days — short enough that 257 of its years would fit into one Earth year.
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