Kepler-442 b
Kepler-442 b is a super-Earth orbiting Kepler-442 in the constellation Lyra. It lies about 1,194 light-years from Earth and was discovered in 2015 using the transit method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
How Big Is Kepler-442 b?
Kepler-442 b has a radius of 1.34 times that of Earth.
Is Kepler-442 b in the Habitable Zone?
Kepler-442 b orbits inside the conservative habitable zone of Kepler-442 — the region where a rocky planet could sustain liquid water on its surface. This makes it one of the most interesting known exoplanets in the search for life.
Habitable zone of Kepler-442: 0.274–0.681 AU (conservative: 0.348–0.646 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-442 b
Kepler-442 b receives 0.66 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-442 b — one full orbit around Kepler-442 — lasts 112.3 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.409 AU — comparable to the inner Solar System. Its orbit is nearly circular (eccentricity 0.040).
How Was Kepler-442 b Discovered?
Kepler-442 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-442 b?
Kepler-442 b is 1,193.6 light-years (366.0 parsecs) from Earth. Light arriving here tonight left the planet about 1,194 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 21,007,360 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-442 b scores 0.84, ranking #17 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-442
Kepler-442
- Surface temperature
- 4,402 K (Sun: 5,772 K)
- Mass
- 0.61 M☉
- Radius
- 0.60 R☉
- Luminosity
- 0.1169 L☉
- Age
- 2.9 billion years (Sun: 4.6)
Planetary System
Kepler-442 b is the only planet known to orbit Kepler-442 so far.
Kepler-442 b — Complete Data
| Radius | 1.340 Earth radii (0.120 Jupiter radii) |
|---|---|
| Orbital period | 112.31 days |
| Orbital distance | 0.409 AU |
| Eccentricity | 0.040 |
| Stellar irradiation | 0.66× Earth |
| Earth Similarity Index | 0.84 |
| Distance from Earth | 1,193.6 light-years (366.0 parsecs) |
| Constellation | Lyra |
| 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-442 b
Is Kepler-442 b habitable?
Kepler-442 b orbits within the habitable zone of Kepler-442, the region where liquid water could exist on a planet's surface. It sits in the conservative habitable zone — the most promising region for habitability. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is Kepler-442 b?
Kepler-442 b is about 1,194 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 21,007,360 years to get there.
How big is Kepler-442 b compared to Earth?
Kepler-442 b has 1.34 times the radius of Earth.
How long is a year on Kepler-442 b?
One orbit around Kepler-442 takes 112.3 Earth days.
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