HD 204313 c
HD 204313 c is a Neptune-like planet orbiting HD 204313 in the constellation Capricornus. It lies about 156 light-years from Earth and was discovered in 2015 using the radial velocity method.
Is HD 204313 c in the Habitable Zone?
The position of HD 204313 c relative to the habitable zone of HD 204313 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 204313 c — one full orbit around HD 204313 — lasts 35.0 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.211 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.06).
How Was HD 204313 c Discovered?
HD 204313 c was discovered in 2015 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 204313 c?
HD 204313 c is 155.9 light-years (47.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1871. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,743,840 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 204313 c scores 0.21, ranking #3,807 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 204313
HD 204313
- Mass
- 1.03 M☉
The HD 204313 Planetary System
HD 204313 c is one of 3 known planets in the HD 204313 system. Its siblings:
- HD 204313 b (Cold Gas Giant)
- HD 204313 e
HD 204313 c — Complete Data
| Mass (best estimate) | 17.16 Earth masses |
|---|---|
| Orbital period | 34.96 days |
| Orbital distance | 0.211 AU |
| Eccentricity | 0.059 |
| Earth Similarity Index | 0.21 |
| Distance from Earth | 155.9 light-years (47.8 parsecs) |
| Constellation | Capricornus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2023-06-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 204313 c
Is HD 204313 c habitable?
HD 204313 c is not known to orbit within the habitable zone of HD 204313, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is HD 204313 c?
HD 204313 c is about 156 light-years from Earth in the constellation Capricornus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,743,840 years to get there.
How long is a year on HD 204313 c?
One orbit around HD 204313 takes 35.0 Earth days — short enough that 10 of its years would fit into one Earth year.
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