GJ 180 b
GJ 180 b is a super-Earth orbiting the M2 V star GJ 180 in the constellation Eridanus. It lies about 39 light-years from Earth and was discovered in 2014 using the radial velocity method.
Is GJ 180 b in the Habitable Zone?
GJ 180 b orbits inside the inner edge of the habitable zone of GJ 180. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of GJ 180: 0.093–0.244 AU (conservative: 0.118–0.231 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 GJ 180 b — one full orbit around GJ 180 — lasts 17.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.092 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.07).
How Was GJ 180 b Discovered?
GJ 180 b was discovered in 2014 using the radial velocity method, with observations from Multiple Observatories.
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 GJ 180 b?
GJ 180 b is 38.9 light-years (11.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1988. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 684,640 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. GJ 180 b scores 0.67, ranking #80 of 5,565 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 180
GJ 180
- Spectral type
- M2 V
- Surface temperature
- 3,371 K (Sun: 5,772 K)
- Mass
- 0.43 M☉
- Luminosity
- 0.0130 L☉
The GJ 180 Planetary System
GJ 180 b is one of 3 known planets in the GJ 180 system. Its siblings:
GJ 180 b — Complete Data
| Mass (best estimate) | 6.49 Earth masses |
|---|---|
| Orbital period | 17.13 days |
| Orbital distance | 0.092 AU |
| Eccentricity | 0.070 |
| Earth Similarity Index | 0.67 |
| Distance from Earth | 38.9 light-years (11.9 parsecs) |
| Constellation | Eridanus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2020-02-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 180 b
Is GJ 180 b habitable?
No — GJ 180 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is GJ 180 b?
GJ 180 b is about 39 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 684,640 years to get there.
How long is a year on GJ 180 b?
One orbit around GJ 180 takes 17.1 Earth days — short enough that 21 of its years would fit into one Earth year.
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