GJ 251 c

A confirmed exoplanet orbiting GJ 251.

Compared with Earth

Mass
About 3.9 times Earth's mass.
Temperature
About -57 °C (-71 °F) from starlight alone, against -18 °C (-1 °F) for Earth measured the same way.
Starlight
About 40% of the starlight Earth gets from the Sun.
Year
A year here lasts about 54 Earth days.

Planet

Radius
Unknown
Mass
3.88 × Earth
Density
Unknown
Equilibrium temperature
216 K
Starlight received
0.404 × Earth
Orbital period
53.65 days
Average distance from its star
0.196 AU

Star

Host star
GJ 251
Spectral class
M — red dwarf
Surface temperature
3,342 K
Radius
0.36 × Sun
Mass
0.35 × Sun
Age
6.8 billion years

System

Distance from Earth
18.2 light-years (5.581 parsecs)
Stars in system
1
Known planets
2

Discovery

Year
2025
Method
Radial Velocity
Facility
Multiple Observatories

Data from the NASA Exoplanet Archive, synced October 14, 2026.