HD 181433 c
HD 181433 c is a cold gas giant orbiting HD 181433 in the constellation Pavo. It lies about 88 light-years from Earth and was discovered in 2008 using the radial velocity method.
Is HD 181433 c in the Habitable Zone?
The position of HD 181433 c relative to the habitable zone of HD 181433 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 181433 c — one full orbit around HD 181433 — lasts 1,018.5 Earth days, longer than an Earth year. It orbits at an average distance of 1.885 AU. Its orbit is mildly elliptical (eccentricity 0.24).
How Was HD 181433 c Discovered?
HD 181433 c was discovered in 2008 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 181433 c?
HD 181433 c is 87.7 light-years (26.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1939. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,543,520 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 181433 c scores 0.16, ranking #4,150 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 181433
HD 181433
- Mass
- 0.86 M☉
The HD 181433 Planetary System
HD 181433 c is one of 3 known planets in the HD 181433 system. Its siblings:
- HD 181433 b (Super Earth)
- HD 181433 d (Cold Gas Giant)
HD 181433 c — Complete Data
| Mass (best estimate) | 235.50 Earth masses |
|---|---|
| Orbital period | 1,018.50 days |
| Orbital distance | 1.885 AU |
| Eccentricity | 0.240 |
| Earth Similarity Index | 0.16 |
| Distance from Earth | 87.7 light-years (26.9 parsecs) |
| Constellation | Pavo |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2008 |
Data: NASA Exoplanet Archive, last updated 2026-03-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 181433 c
Is HD 181433 c habitable?
HD 181433 c is not known to orbit within the habitable zone of HD 181433, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 181433 c?
HD 181433 c is about 88 light-years from Earth in the constellation Pavo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,543,520 years to get there.
How long is a year on HD 181433 c?
One orbit around HD 181433 takes 1,018.5 Earth days.
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