The GJ 251 System
GJ 251 is a planetary system in the constellation Gemini hosting 2 confirmed exoplanets, about 18 light-years from Earth. One of its planets orbits within the habitable zone, where liquid water could exist on a planetary surface.
GJ 251: Star and Habitable Zone
GJ 251
- Surface temperature
- 3,342 K (Sun: 5,772 K)
- Mass
- 0.35 M☉
- Radius
- 0.36 R☉
- Luminosity
- 0.0155 L☉
- Age
- 6.8 billion years (Sun: 4.6)
Habitable zone of GJ 251: 0.102–0.267 AU (conservative: 0.129–0.253 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 ›
All 2 Planets in the GJ 251 System
Discovery History
The first planet found here, GJ 251 b, was discovered in 2020 using the radial velocity method. The most recent addition, GJ 251 c, followed in 2025.
Frequently Asked Questions About GJ 251
How many planets does GJ 251 have?
GJ 251 has 2 confirmed exoplanets. More may await discovery.
Are any planets in the GJ 251 system habitable?
One planet in the system orbits within the habitable zone, where liquid water could exist. Actual habitability depends on atmospheres and composition, which are not yet known.
How far away is GJ 251?
GJ 251 is about 18 light-years from Earth in the constellation Gemini.
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