HIP 12961 b
HIP 12961 b is a cold gas giant orbiting HIP 12961 in the constellation Eridanus. It lies about 76 light-years from Earth and was discovered in 2010 using the radial velocity method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
Is HIP 12961 b in the Habitable Zone?
HIP 12961 b orbits within the optimistic habitable zone of HIP 12961 — the broader region where liquid water might be possible under favorable atmospheric conditions.
Habitable zone of HIP 12961: 0.241–0.613 AU (conservative: 0.305–0.581 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 HIP 12961 b — one full orbit around HIP 12961 — lasts 57.4 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.250 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.17).
How Was HIP 12961 b Discovered?
HIP 12961 b was discovered in 2010 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 HIP 12961 b?
HIP 12961 b is 76.2 light-years (23.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1950. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,341,120 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. HIP 12961 b scores 0.37, ranking #626 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HIP 12961
HIP 12961
- Surface temperature
- 3,901 K (Sun: 5,772 K)
- Mass
- 0.69 M☉
- Radius
- 0.65 R☉
Planetary System
HIP 12961 b is the only planet known to orbit HIP 12961 so far.
HIP 12961 b — Complete Data
| Mass (best estimate) | 114.42 Earth masses |
|---|---|
| Orbital period | 57.44 days |
| Orbital distance | 0.250 AU |
| Eccentricity | 0.170 |
| Earth Similarity Index | 0.37 |
| Distance from Earth | 76.2 light-years (23.4 parsecs) |
| Constellation | Eridanus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2018-09-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HIP 12961 b
Is HIP 12961 b habitable?
HIP 12961 b orbits within the habitable zone of HIP 12961, the region where liquid water could exist on a planet's surface. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is HIP 12961 b?
HIP 12961 b is about 76 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,341,120 years to get there.
How long is a year on HIP 12961 b?
One orbit around HIP 12961 takes 57.4 Earth days.
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