HD 82943 b
HD 82943 b is a cold gas giant orbiting HD 82943 in the constellation Hydra. It lies about 90 light-years from Earth and was discovered in 2003 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 HD 82943 b in the Habitable Zone?
HD 82943 b orbits inside the conservative habitable zone of HD 82943 — 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 HD 82943: 0.929–2.181 AU (conservative: 1.177–2.068 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 82943 b — one full orbit around HD 82943 — lasts 441.5 Earth days, longer than an Earth year. It orbits at an average distance of 1.183 AU. Its orbit is mildly elliptical (eccentricity 0.16).
How Was HD 82943 b Discovered?
HD 82943 b was discovered in 2003 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 82943 b?
HD 82943 b is 90.0 light-years (27.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1936. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,584,000 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 82943 b scores 0.39, ranking #531 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 82943
HD 82943
- Surface temperature
- 5,935 K (Sun: 5,772 K)
- Mass
- 1.08 M☉
- Radius
- 1.18 R☉
- Luminosity
- 1.5633 L☉
The HD 82943 Planetary System
HD 82943 b is one of 2 known planets in the HD 82943 system. Its siblings:
- HD 82943 c (Cold Gas Giant)
HD 82943 b — Complete Data
| Mass | 534.25 Earth masses (1.681 Jupiter masses) |
|---|---|
| Orbital period | 441.47 days |
| Orbital distance | 1.183 AU |
| Eccentricity | 0.162 |
| Earth Similarity Index | 0.39 |
| Distance from Earth | 90.0 light-years (27.6 parsecs) |
| Constellation | Hydra |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2003 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 82943 b
Is HD 82943 b habitable?
HD 82943 b orbits within the habitable zone of HD 82943, 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 HD 82943 b?
HD 82943 b is about 90 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,584,000 years to get there.
How long is a year on HD 82943 b?
One orbit around HD 82943 takes 441.5 Earth days.
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