Gliese 12 b
Gliese 12 b is a terrestrial planet orbiting Gliese 12 in the constellation Pisces. It lies about 40 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is Gliese 12 b?
Gliese 12 b has a radius of 0.93 times that of Earth. Its mass is 0.95 times that of Earth, giving it a density of 6.40 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is Gliese 12 b in the Habitable Zone?
The position of Gliese 12 b relative to the habitable zone of Gliese 12 cannot be precisely determined from the available orbital data.
Habitable zone of Gliese 12: 0.072–0.189 AU (conservative: 0.091–0.179 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 ›
Orbit and Year Length
A year on Gliese 12 b — one full orbit around Gliese 12 — lasts 12.8 Earth days, shorter than Mercury's 88-day year. Its orbit is mildly elliptical (eccentricity 0.24).
How Was Gliese 12 b Discovered?
Gliese 12 b was discovered in 2024 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is Gliese 12 b?
Gliese 12 b is 39.8 light-years (12.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1987. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 700,480 years to make the journey.
The Host Star: Gliese 12
Gliese 12
- Surface temperature
- 3,328 K (Sun: 5,772 K)
- Mass
- 0.26 M☉
- Radius
- 0.27 R☉
- Age
- 7.0 billion years (Sun: 4.6)
Planetary System
Gliese 12 b is the only planet known to orbit Gliese 12 so far.
Gliese 12 b — Complete Data
| Radius | 0.930 Earth radii (0.083 Jupiter radii) |
|---|---|
| Mass | 0.95 Earth masses (0.003 Jupiter masses) |
| Density | 6.40 g/cm³ (Earth: 5.51) |
| Orbital period | 12.76 days |
| Eccentricity | 0.240 |
| Distance from Earth | 39.8 light-years (12.2 parsecs) |
| Constellation | Pisces |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2026-03-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Gliese 12 b
Is Gliese 12 b habitable?
Gliese 12 b is not known to orbit within the habitable zone of Gliese 12, and as a terrestrial planet it is an unlikely candidate for life as we know it.
How far away is Gliese 12 b?
Gliese 12 b is about 40 light-years from Earth in the constellation Pisces. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 700,480 years to get there.
How big is Gliese 12 b compared to Earth?
Gliese 12 b has 0.93 times the radius of Earth and about 0.95 times its mass.
How long is a year on Gliese 12 b?
One orbit around Gliese 12 takes 12.8 Earth days — short enough that 29 of its years would fit into one Earth year.
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