GJ 1289 b
GJ 1289 b is a super-Earth orbiting the M4.5 Ve star GJ 1289 in the constellation Andromeda. It lies about 27 light-years from Earth and was discovered in 2024 using the radial velocity method.
Is GJ 1289 b in the Habitable Zone?
The position of GJ 1289 b relative to the habitable zone of GJ 1289 cannot be precisely determined from the available orbital data.
Temperature on GJ 1289 b
The equilibrium temperature of GJ 1289 b is about 150 K (-123 °C) — well below freezing. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on GJ 1289 b — one full orbit around GJ 1289 — lasts 111.7 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.270 AU — closer to its star than Mercury is to the Sun.
How Was GJ 1289 b Discovered?
GJ 1289 b was discovered in 2024 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 1289 b?
GJ 1289 b is 27.2 light-years (8.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1999. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 478,720 years to make the journey.
The Host Star: GJ 1289
GJ 1289
- Spectral type
- M4.5 Ve
- Surface temperature
- 3,296 K (Sun: 5,772 K)
- Mass
- 0.21 M☉
Planetary System
GJ 1289 b is the only planet known to orbit GJ 1289 so far.
GJ 1289 b — Complete Data
| Mass (best estimate) | 6.27 Earth masses |
|---|---|
| Orbital period | 111.74 days |
| Orbital distance | 0.270 AU |
| Equilibrium temperature | 150 K (-123 °C) |
| Distance from Earth | 27.2 light-years (8.4 parsecs) |
| Constellation | Andromeda |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2025-03-18. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 1289 b
Is GJ 1289 b habitable?
GJ 1289 b is not known to orbit within the habitable zone of GJ 1289, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is GJ 1289 b?
GJ 1289 b is about 27 light-years from Earth in the constellation Andromeda. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 478,720 years to get there.
How long is a year on GJ 1289 b?
One orbit around GJ 1289 takes 111.7 Earth days.
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