GJ 625 b
GJ 625 b is a super-Earth orbiting the M2 star GJ 625 in the constellation Draco. It lies about 21 light-years from Earth and was discovered in 2017 using the radial velocity method.
Is GJ 625 b in the Habitable Zone?
GJ 625 b orbits inside the inner edge of the habitable zone of GJ 625. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of GJ 625: 0.092–0.240 AU (conservative: 0.117–0.227 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 625 b — one full orbit around GJ 625 — lasts 14.6 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.078 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.13).
How Was GJ 625 b Discovered?
GJ 625 b was discovered in 2017 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 625 b?
GJ 625 b is 21.1 light-years (6.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 2005. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 371,360 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. GJ 625 b scores 0.71, ranking #55 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 625
GJ 625
- Spectral type
- M2
- Surface temperature
- 3,499 K (Sun: 5,772 K)
- Mass
- 0.30 M☉
- Radius
- 0.31 R☉
- Luminosity
- 0.0128 L☉
Planetary System
GJ 625 b is the only planet known to orbit GJ 625 so far.
GJ 625 b — Complete Data
| Mass (best estimate) | 2.82 Earth masses |
|---|---|
| Orbital period | 14.63 days |
| Orbital distance | 0.078 AU |
| Eccentricity | 0.130 |
| Earth Similarity Index | 0.71 |
| Distance from Earth | 21.1 light-years (6.5 parsecs) |
| Constellation | Draco |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2017 |
Data: NASA Exoplanet Archive, last updated 2017-09-27. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 625 b
Is GJ 625 b habitable?
No — GJ 625 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is GJ 625 b?
GJ 625 b is about 21 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 371,360 years to get there.
How long is a year on GJ 625 b?
One orbit around GJ 625 takes 14.6 Earth days — short enough that 25 of its years would fit into one Earth year.
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