HD 72659 c
HD 72659 c is a exoplanet orbiting the G2 V star HD 72659 in the constellation Hydra. It lies about 169 light-years from Earth and was discovered in 2022 using the radial velocity method.
Is HD 72659 c in the Habitable Zone?
HD 72659 c orbits beyond the outer edge of the habitable zone of HD 72659. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 72659: 1.065–2.499 AU (conservative: 1.349–2.370 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 HD 72659 c — one full orbit around HD 72659 — lasts 35,500.0 Earth days, longer than Jupiter's 12-year orbit. It orbits at an average distance of 21.500 AU. Its orbit is mildly elliptical (eccentricity 0.11).
How Was HD 72659 c Discovered?
HD 72659 c was discovered in 2022 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 HD 72659 c?
HD 72659 c is 169.3 light-years (51.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1857. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,979,680 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. HD 72659 c scores 0.09, ranking #4,553 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 72659
HD 72659
- Spectral type
- G2 V
- Surface temperature
- 5,929 K (Sun: 5,772 K)
- Mass
- 1.03 M☉
- Radius
- 1.36 R☉
- Age
- 8.0 billion years (Sun: 4.6)
The HD 72659 Planetary System
HD 72659 c is one of 2 known planets in the HD 72659 system. Its siblings:
- HD 72659 b (Cold Gas Giant)
HD 72659 c — Complete Data
| Mass | 6,165.87 Earth masses (19.400 Jupiter masses) |
|---|---|
| Orbital period | 35,500.00 days |
| Orbital distance | 21.500 AU |
| Eccentricity | 0.114 |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 169.3 light-years (51.9 parsecs) |
| Constellation | Hydra |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2025-12-11. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 72659 c
Is HD 72659 c habitable?
No — HD 72659 c orbits outside the habitable zone of HD 72659 and is likely too cold for liquid water on its surface.
How far away is HD 72659 c?
HD 72659 c is about 169 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,979,680 years to get there.
How long is a year on HD 72659 c?
One orbit around HD 72659 takes 35,500.0 Earth days.
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