HD 204941 b
HD 204941 b is a cold gas giant orbiting HD 204941 in the constellation Capricornus. It lies about 94 light-years from Earth and was discovered in 2011 using the radial velocity method.
Is HD 204941 b in the Habitable Zone?
HD 204941 b orbits beyond the outer edge of the habitable zone of HD 204941. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 204941: 0.462–1.115 AU (conservative: 0.585–1.057 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 204941 b — one full orbit around HD 204941 — lasts 1,733.0 Earth days, longer than an Earth year. It orbits at an average distance of 2.550 AU. Its orbit is highly elliptical (eccentricity 0.37), swinging dramatically closer to and farther from its star.
How Was HD 204941 b Discovered?
HD 204941 b was discovered in 2011 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 204941 b?
HD 204941 b is 93.7 light-years (28.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1933. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,649,120 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. HD 204941 b scores 0.14, ranking #4,260 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 204941
HD 204941 b belongs to a system of 2 stars; it orbits HD 204941.
HD 204941
- Surface temperature
- 5,026 K (Sun: 5,772 K)
- Mass
- 0.58 M☉
- Radius
- 0.78 R☉
Planetary System
HD 204941 b is the only planet known to orbit HD 204941 so far.
HD 204941 b — Complete Data
| Mass (best estimate) | 73.10 Earth masses |
|---|---|
| Orbital period | 1,733.00 days |
| Orbital distance | 2.550 AU |
| Eccentricity | 0.370 |
| Earth Similarity Index | 0.14 |
| Distance from Earth | 93.7 light-years (28.7 parsecs) |
| Constellation | Capricornus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2018-09-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 204941 b
Is HD 204941 b habitable?
No — HD 204941 b orbits outside the habitable zone of HD 204941 and is likely too cold for liquid water on its surface.
How far away is HD 204941 b?
HD 204941 b is about 94 light-years from Earth in the constellation Capricornus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,649,120 years to get there.
How long is a year on HD 204941 b?
One orbit around HD 204941 takes 1,733.0 Earth days.
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