Plate No. 6,072 — in order of discoveryEntered 2026-08-20

Gl 725 B c

A cold super-earth world orbiting Gl 725 B, a M4 star, 22.3 ly from Earth.

Enter the system →Find it in the night sky →

Tonight's light from Gl 725 B left the star around 2004.

1 worldtemperate zone1s = 1s

Orbit shapes and relative timing are true — worlds sweep faster near their star, as Kepler demands. Spacing is drawn to true scale when the system allows; wide systems open compressed so inner and outer worlds share the page. Dashed orbits are derived from period alone.

The measures

Earth

1.0 R⊕

Gl 725 B c

1.66 R⊕

frozenEarth 255 K · c 215 Kstar-hot

Life outlook

Conceivable

38/ 100

Warmth: 59 · weight 40%
Size: 28 · weight 30%
Star: 17 · weight 20%
Orbit: unmeasured · weight 10%

A strict Earth-similarity index, not a detection: every factor peaks at Earth's own value and they multiply, so one hostile factor sinks the score — only a true Earth twin would reach 100. Equilibrium temperature ignores atmospheres, which can warm a cold world into comfort, or turn a Venus into a furnace.

The world

Class: Super-Earth
Radius: 1.66 R⊕
Mass: 3.4 M⊕
Density: 4.08 g/cm³
Equilibrium temperature: 215 K
Starlight received: 0.47× Earth

The orbit

Period: 37.9 days
Semi-major axis: 0.139 AU
Eccentricity: —

The star

Host: Gl 725 B
Spectral type: M4
Temperature: 3,379 K
Radius: 0.28 R☉
Mass: 0.25 M☉

The system

Distance: 22.3 ly · 6.8 pc
Known planets: 2
Stars: 2
Coordinates: RA 280.7° · Dec 59.63°

The observation

Star brightness: V 9.7 · telescope
Atmospheric spectra: none yet
Stellar age: 8.7 Gyr

The record

Method: Radial Velocity
Facility: Mauna Kea Observatory
Discovery: 2026
Parameters published: —