HD 217958 b
HD 217958 b is a cold gas giant orbiting HD 217958 in the constellation Piscis Austrinus. It lies about 202 light-years from Earth and was discovered in 2022 using the radial velocity method.
Is HD 217958 b in the Habitable Zone?
The position of HD 217958 b relative to the habitable zone of HD 217958 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 217958 b — one full orbit around HD 217958 — lasts 2,560.2 Earth days, longer than an Earth year. It orbits at an average distance of 3.758 AU. Its orbit is mildly elliptical (eccentricity 0.16).
How Was HD 217958 b Discovered?
HD 217958 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 217958 b?
HD 217958 b is 201.6 light-years (61.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1825. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,548,160 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 217958 b scores 0.19, ranking #3,996 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 217958
HD 217958
- Mass
- 1.08 M☉
Planetary System
HD 217958 b is the only planet known to orbit HD 217958 so far.
HD 217958 b — Complete Data
| Mass | 166.54 Earth masses (0.524 Jupiter masses) |
|---|---|
| Orbital period | 2,560.20 days |
| Orbital distance | 3.758 AU |
| Eccentricity | 0.156 |
| Earth Similarity Index | 0.19 |
| Distance from Earth | 201.6 light-years (61.8 parsecs) |
| Constellation | Piscis Austrinus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2023-06-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 217958 b
Is HD 217958 b habitable?
HD 217958 b is not known to orbit within the habitable zone of HD 217958, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 217958 b?
HD 217958 b is about 202 light-years from Earth in the constellation Piscis Austrinus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,548,160 years to get there.
How long is a year on HD 217958 b?
One orbit around HD 217958 takes 2,560.2 Earth days.
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