HD 125136 b
HD 125136 b is a cold gas giant orbiting HD 125136 in the constellation Apus. It lies about 396 light-years from Earth and was discovered in 2026 using the radial velocity method.
Is HD 125136 b in the Habitable Zone?
The position of HD 125136 b relative to the habitable zone of HD 125136 cannot be precisely determined from the available orbital data.
Habitable zone of HD 125136: 3.119–7.555 AU (conservative: 3.951–7.162 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HD 125136 b — one full orbit around HD 125136 — lasts 849.8 Earth days, longer than an Earth year. Its orbit is mildly elliptical (eccentricity 0.05).
How Was HD 125136 b Discovered?
HD 125136 b was discovered in 2026 using the radial velocity method, with observations from La Silla 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 HD 125136 b?
HD 125136 b is 395.5 light-years (121.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1631. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 6,960,800 years to make the journey.
The Host Star: HD 125136
HD 125136
- Surface temperature
- 4,959 K (Sun: 5,772 K)
- Mass
- 1.55 M☉
- Radius
- 5.39 R☉
- Luminosity
- 15.8001 L☉
- Age
- 4.0 billion years (Sun: 4.6)
Planetary System
HD 125136 b is the only planet known to orbit HD 125136 so far.
HD 125136 b — Complete Data
| Mass (best estimate) | 718.29 Earth masses |
|---|---|
| Orbital period | 849.77 days |
| Eccentricity | 0.050 |
| Distance from Earth | 395.5 light-years (121.3 parsecs) |
| Constellation | Apus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2026 |
Data: NASA Exoplanet Archive, last updated 2026-07-02. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 125136 b
Is HD 125136 b habitable?
HD 125136 b is not known to orbit within the habitable zone of HD 125136, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 125136 b?
HD 125136 b is about 396 light-years from Earth in the constellation Apus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 6,960,800 years to get there.
How long is a year on HD 125136 b?
One orbit around HD 125136 takes 849.8 Earth days.
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