Gl 686 b
Gl 686 b is a super-Earth orbiting Gl 686 in the constellation Hercules. It lies about 27 light-years from Earth and was discovered in 2018 using the radial velocity method.
Is Gl 686 b in the Habitable Zone?
Gl 686 b orbits inside the inner edge of the habitable zone of Gl 686. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Gl 686: 0.140–0.361 AU (conservative: 0.178–0.342 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 ›
Orbit and Year Length
A year on Gl 686 b — one full orbit around Gl 686 — lasts 15.5 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.091 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.05).
How Was Gl 686 b Discovered?
Gl 686 b was discovered in 2018 using the radial velocity method, with observations from Roque de los Muchachos Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is Gl 686 b?
Gl 686 b is 26.6 light-years (8.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 2000. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 468,160 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. Gl 686 b scores 0.50, ranking #249 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Gl 686
Gl 686
- Surface temperature
- 3,656 K (Sun: 5,772 K)
- Mass
- 0.43 M☉
- Radius
- 0.43 R☉
- Luminosity
- 0.0295 L☉
Planetary System
Gl 686 b is the only planet known to orbit Gl 686 so far.
Gl 686 b — Complete Data
| Mass (best estimate) | 6.62 Earth masses |
|---|---|
| Orbital period | 15.53 days |
| Orbital distance | 0.091 AU |
| Eccentricity | 0.050 |
| Earth Similarity Index | 0.50 |
| Distance from Earth | 26.6 light-years (8.2 parsecs) |
| Constellation | Hercules |
| Discovery method | Radial Velocity |
| Discovery facility | Roque de los Muchachos Observatory |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2020-12-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Gl 686 b
Is Gl 686 b habitable?
No — Gl 686 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Gl 686 b?
Gl 686 b is about 27 light-years from Earth in the constellation Hercules. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 468,160 years to get there.
How long is a year on Gl 686 b?
One orbit around Gl 686 takes 15.5 Earth days — short enough that 24 of its years would fit into one Earth year.
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