HD 82943 c
HD 82943 c 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.
Is HD 82943 c in the Habitable Zone?
HD 82943 c orbits inside the inner edge of the habitable zone of HD 82943. So close to its star, surface conditions are far too hot for liquid water.
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.
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Orbit and Year Length
A year on HD 82943 c — one full orbit around HD 82943 — lasts 220.1 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.743 AU — comparable to the inner Solar System. Its orbit is highly elliptical (eccentricity 0.37), swinging dramatically closer to and farther from its star.
How Was HD 82943 c Discovered?
HD 82943 c 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 c?
HD 82943 c 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 c scores 0.29, ranking #1,600 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 c is one of 2 known planets in the HD 82943 system. Its siblings:
- HD 82943 b (Cold Gas Giant)
HD 82943 c — Complete Data
| Mass | 622.60 Earth masses (1.959 Jupiter masses) |
|---|---|
| Orbital period | 220.08 days |
| Orbital distance | 0.743 AU |
| Eccentricity | 0.366 |
| Earth Similarity Index | 0.29 |
| 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 c
Is HD 82943 c habitable?
No — HD 82943 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 82943 c?
HD 82943 c 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 c?
One orbit around HD 82943 takes 220.1 Earth days.
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