HD 168443 b
HD 168443 b is a cold gas giant orbiting HD 168443 in the constellation Serpens. It lies about 129 light-years from Earth and was discovered in 1998 using the radial velocity method.
Is HD 168443 b in the Habitable Zone?
The position of HD 168443 b relative to the habitable zone of HD 168443 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 168443 b — one full orbit around HD 168443 — lasts 58.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.292 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.53), swinging dramatically closer to and farther from its star.
How Was HD 168443 b Discovered?
HD 168443 b was discovered in 1998 using the radial velocity method, with observations from W. M. Keck 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 168443 b?
HD 168443 b is 129.2 light-years (39.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1897. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,273,920 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 168443 b scores 0.10, ranking #4,428 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 168443
HD 168443
- Mass
- 0.98 M☉
The HD 168443 Planetary System
HD 168443 b is one of 2 known planets in the HD 168443 system. Its siblings:
HD 168443 b — Complete Data
| Mass (best estimate) | 2,424.40 Earth masses |
|---|---|
| Orbital period | 58.11 days |
| Orbital distance | 0.292 AU |
| Eccentricity | 0.530 |
| Earth Similarity Index | 0.10 |
| Distance from Earth | 129.2 light-years (39.6 parsecs) |
| Constellation | Serpens |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 1998 |
Data: NASA Exoplanet Archive, last updated 2023-06-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 168443 b
Is HD 168443 b habitable?
HD 168443 b is not known to orbit within the habitable zone of HD 168443, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 168443 b?
HD 168443 b is about 129 light-years from Earth in the constellation Serpens. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,273,920 years to get there.
How long is a year on HD 168443 b?
One orbit around HD 168443 takes 58.1 Earth days.
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