G 261-6 b
G 261-6 b is a terrestrial planet orbiting the M5.5 V star G 261-6 in the constellation Draco. It lies about 35 light-years from Earth and was discovered in 2025 using the radial velocity method.
Is G 261-6 b in the Habitable Zone?
The position of G 261-6 b relative to the habitable zone of G 261-6 cannot be precisely determined from the available orbital data.
Temperature on G 261-6 b
The equilibrium temperature of G 261-6 b is about 322 K (49 °C) — in a range broadly comparable to Earth, whose equilibrium temperature is 255 K. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 1.80 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on G 261-6 b — one full orbit around G 261-6 — lasts 5.45 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.030 AU — closer to its star than Mercury is to the Sun.
How Was G 261-6 b Discovered?
G 261-6 b was discovered in 2025 using the radial velocity method, with observations from Calar Alto Observatory.
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 G 261-6 b?
G 261-6 b is 34.7 light-years (10.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1992. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 610,720 years to make the journey.
The Host Star: G 261-6
G 261-6
- Spectral type
- M5.5 V
- Mass
- 0.12 M☉
Planetary System
G 261-6 b is the only planet known to orbit G 261-6 so far.
G 261-6 b — Complete Data
| Mass (best estimate) | 1.37 Earth masses |
|---|---|
| Orbital period | 5.45 days |
| Orbital distance | 0.030 AU |
| Equilibrium temperature | 322 K (49 °C) |
| Stellar irradiation | 1.80× Earth |
| Distance from Earth | 34.7 light-years (10.6 parsecs) |
| Constellation | Draco |
| Discovery method | Radial Velocity |
| Discovery facility | Calar Alto Observatory |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-04-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About G 261-6 b
Is G 261-6 b habitable?
G 261-6 b is not known to orbit within the habitable zone of G 261-6, and as a terrestrial planet it is an unlikely candidate for life as we know it.
How far away is G 261-6 b?
G 261-6 b is about 35 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 610,720 years to get there.
How long is a year on G 261-6 b?
One orbit around G 261-6 takes 5.5 Earth days — short enough that 67 of its years would fit into one Earth year.
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