HIP 67851 c
HIP 67851 c is a cold gas giant orbiting the K0 III star HIP 67851 in the constellation Centaurus. It lies about 209 light-years from Earth and was discovered in 2015 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 67851 c in the Habitable Zone?
HIP 67851 c orbits inside the conservative habitable zone of HIP 67851 — the region where a rocky planet could sustain liquid water on its surface. This makes it one of the most interesting known exoplanets in the search for life.
Habitable zone of HIP 67851: 3.023–7.357 AU (conservative: 3.829–6.975 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 67851 c — one full orbit around HIP 67851 — lasts 3,128.4 Earth days, longer than an Earth year. It orbits at an average distance of 4.550 AU. Its orbit is highly elliptical (eccentricity 0.30), swinging dramatically closer to and farther from its star.
How Was HIP 67851 c Discovered?
HIP 67851 c was discovered in 2015 using the radial velocity method, with observations from Multiple Observatories.
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 67851 c?
HIP 67851 c is 209.1 light-years (64.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1817. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,680,160 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 67851 c scores 0.35, ranking #800 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HIP 67851
HIP 67851
- Spectral type
- K0 III
- Surface temperature
- 4,840 K (Sun: 5,772 K)
- Mass
- 1.28 M☉
- Radius
- 5.45 R☉
- Luminosity
- 14.6801 L☉
The HIP 67851 Planetary System
HIP 67851 c is one of 2 known planets in the HIP 67851 system. Its siblings:
- HIP 67851 b (Cold Gas Giant)
HIP 67851 c — Complete Data
| Mass (best estimate) | 1,579.61 Earth masses |
|---|---|
| Orbital period | 3,128.41 days |
| Orbital distance | 4.550 AU |
| Eccentricity | 0.300 |
| Earth Similarity Index | 0.35 |
| Distance from Earth | 209.1 light-years (64.1 parsecs) |
| Constellation | Centaurus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2025-05-27. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HIP 67851 c
Is HIP 67851 c habitable?
HIP 67851 c orbits within the habitable zone of HIP 67851, the region where liquid water could exist on a planet's surface. It sits in the conservative habitable zone — the most promising region for habitability. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is HIP 67851 c?
HIP 67851 c is about 209 light-years from Earth in the constellation Centaurus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,680,160 years to get there.
How long is a year on HIP 67851 c?
One orbit around HIP 67851 takes 3,128.4 Earth days.
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