HD 205158 b
HD 205158 b is a cold gas giant orbiting HD 205158 in the constellation Indus. It lies about 283 light-years from Earth and was discovered in 2022 using the radial velocity method.
Is HD 205158 b in the Habitable Zone?
The position of HD 205158 b relative to the habitable zone of HD 205158 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 205158 b — one full orbit around HD 205158 — lasts 25.3 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.177 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.14).
How Was HD 205158 b Discovered?
HD 205158 b was discovered in 2022 using the radial velocity method, with observations from Multiple Observatories.
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 205158 b?
HD 205158 b is 282.5 light-years (86.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1744. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,972,000 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 205158 b scores 0.07, ranking #4,888 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 205158
HD 205158
- Mass
- 1.16 M☉
Planetary System
HD 205158 b is the only planet known to orbit HD 205158 so far.
HD 205158 b — Complete Data
| Mass (best estimate) | 124.59 Earth masses |
|---|---|
| Orbital period | 25.34 days |
| Orbital distance | 0.177 AU |
| Eccentricity | 0.145 |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 282.5 light-years (86.6 parsecs) |
| Constellation | Indus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2023-06-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 205158 b
Is HD 205158 b habitable?
HD 205158 b is not known to orbit within the habitable zone of HD 205158, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 205158 b?
HD 205158 b is about 283 light-years from Earth in the constellation Indus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,972,000 years to get there.
How long is a year on HD 205158 b?
One orbit around HD 205158 takes 25.3 Earth days — short enough that 14 of its years would fit into one Earth year.
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