Kepler-436 b
Kepler-436 b is a mini-Neptune orbiting Kepler-436 in the constellation Cygnus. It lies about 1,921 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is Kepler-436 b?
Kepler-436 b has a radius of 2.73 times that of Earth.
Is Kepler-436 b in the Habitable Zone?
Kepler-436 b orbits inside the inner edge of the habitable zone of Kepler-436. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-436: 0.371–0.908 AU (conservative: 0.470–0.861 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-436 b
Kepler-436 b receives 1.69 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-436 b — one full orbit around Kepler-436 — lasts 64.0 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.339 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.19).
How Was Kepler-436 b Discovered?
Kepler-436 b was discovered in 2015 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-436 b?
Kepler-436 b is 1,920.6 light-years (588.9 parsecs) from Earth. Light arriving here tonight left the planet about 1,921 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 33,802,560 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-436 b scores 0.62, ranking #116 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-436
Kepler-436
- Surface temperature
- 4,685 K (Sun: 5,772 K)
- Mass
- 0.75 M☉
- Radius
- 0.71 R☉
- Age
- 4.1 billion years (Sun: 4.6)
The Kepler-436 Planetary System
Kepler-436 b is one of 2 known planets in the Kepler-436 system. Its siblings:
- Kepler-436 c (Mini Neptune)
Kepler-436 b — Complete Data
| Radius | 2.730 Earth radii (0.240 Jupiter radii) |
|---|---|
| Orbital period | 64.00 days |
| Orbital distance | 0.339 AU |
| Eccentricity | 0.190 |
| Stellar irradiation | 1.69× Earth |
| Earth Similarity Index | 0.62 |
| Distance from Earth | 1,920.6 light-years (588.9 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2015-01-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-436 b
Is Kepler-436 b habitable?
No — Kepler-436 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-436 b?
Kepler-436 b is about 1,921 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 33,802,560 years to get there.
How big is Kepler-436 b compared to Earth?
Kepler-436 b has 2.73 times the radius of Earth.
How long is a year on Kepler-436 b?
One orbit around Kepler-436 takes 64.0 Earth days.
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