GJ 1151 c
GJ 1151 c is a Neptune-like planet orbiting the M 4.5V star GJ 1151 in the constellation Ursa Major. It lies about 26 light-years from Earth and was discovered in 2023 using the radial velocity method.
Is GJ 1151 c in the Habitable Zone?
GJ 1151 c orbits beyond the outer edge of the habitable zone of GJ 1151. At that distance, any surface water would almost certainly be frozen.
Habitable zone of GJ 1151: 0.047–0.124 AU (conservative: 0.060–0.117 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 1151 c — one full orbit around GJ 1151 — lasts 389.7 Earth days, longer than an Earth year. It orbits at an average distance of 0.571 AU — comparable to the inner Solar System.
How Was GJ 1151 c Discovered?
GJ 1151 c was discovered in 2023 using the radial velocity method, with observations from Multiple Facilities.
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 1151 c?
GJ 1151 c is 26.2 light-years (8.0 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 461,120 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 1151 c scores 0.21, ranking #3,743 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 1151
GJ 1151
- Spectral type
- M 4.5V
- Surface temperature
- 3,280 K (Sun: 5,772 K)
- Mass
- 0.16 M☉
- Radius
- 0.18 R☉
- Luminosity
- 0.0033 L☉
Planetary System
GJ 1151 c is the only planet known to orbit GJ 1151 so far.
GJ 1151 c — Complete Data
| Mass (best estimate) | 10.62 Earth masses |
|---|---|
| Orbital period | 389.70 days |
| Orbital distance | 0.571 AU |
| Earth Similarity Index | 0.21 |
| Distance from Earth | 26.2 light-years (8.0 parsecs) |
| Constellation | Ursa Major |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Facilities |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-01-23. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 1151 c
Is GJ 1151 c habitable?
No — GJ 1151 c orbits outside the habitable zone of GJ 1151 and is likely too cold for liquid water on its surface.
How far away is GJ 1151 c?
GJ 1151 c is about 26 light-years from Earth in the constellation Ursa Major. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 461,120 years to get there.
How long is a year on GJ 1151 c?
One orbit around GJ 1151 takes 389.7 Earth days.
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