Kepler-139 b
Kepler-139 b is a mini-Neptune orbiting Kepler-139 in the constellation Lyra. It lies about 1,275 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-139 b?
Kepler-139 b has a radius of 2.94 times that of Earth.
Is Kepler-139 b in the Habitable Zone?
The position of Kepler-139 b relative to the habitable zone of Kepler-139 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on Kepler-139 b — one full orbit around Kepler-139 — lasts 15.8 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.127 AU — closer to its star than Mercury is to the Sun.
How Was Kepler-139 b Discovered?
Kepler-139 b 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-139 b?
Kepler-139 b is 1,275.4 light-years (391.0 parsecs) from Earth. Light arriving here tonight left the planet about 1,275 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 22,447,040 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-139 b scores 0.23, ranking #3,492 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-139
Kepler-139
- Mass
- 1.08 M☉
The Kepler-139 Planetary System
Kepler-139 b is one of 5 known planets in the Kepler-139 system. Its siblings:
- Kepler-139 c (Sub Neptune)
- Kepler-139 d (Super Earth)
- Kepler-139 e (Cold Gas Giant)
- Kepler-139 f (Neptune-like)
Kepler-139 b — Complete Data
| Radius | 2.940 Earth radii (0.262 Jupiter radii) |
|---|---|
| Orbital period | 15.77 days |
| Orbital distance | 0.127 AU |
| Earth Similarity Index | 0.23 |
| Distance from Earth | 1,275.4 light-years (391.0 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-139 b
Is Kepler-139 b habitable?
Kepler-139 b is not known to orbit within the habitable zone of Kepler-139, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is Kepler-139 b?
Kepler-139 b is about 1,275 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 22,447,040 years to get there.
How big is Kepler-139 b compared to Earth?
Kepler-139 b has 2.94 times the radius of Earth.
How long is a year on Kepler-139 b?
One orbit around Kepler-139 takes 15.8 Earth days — short enough that 23 of its years would fit into one Earth year.
Explore Kepler-139 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
