K2-138 c

A confirmed exoplanet orbiting K2-138.

Compared with Earth

Size
About 2.3 times Earth's width.
Mass
About 6.3 times Earth's mass.
Year
A year here lasts about 3.6 Earth days.

Planet

Radius
2.299 × Earth
Mass
6.31 × Earth
Density
2.8 g/cm³
Equilibrium temperature
Unknown
Starlight received
Unknown
Orbital period
3.56 days
Average distance from its star
0.04461 AU

Star

Host star
K2-138
Spectral class
G — sun-like
Surface temperature
5,356 K
Radius
0.863 × Sun
Mass
0.935 × Sun
Age
2.8 billion years

System

Distance from Earth
660.7 light-years (202.6 parsecs)
Stars in system
1
Known planets
6

Discovery

Year
2017
Method
Transit
Facility
K2

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