HD 206255 b
HD 206255 b is a Neptune-like planet orbiting the G5 IV/V star HD 206255 in the constellation Indus. It lies about 245 light-years from Earth and was discovered in 2019 using the radial velocity method.
Is HD 206255 b in the Habitable Zone?
The position of HD 206255 b relative to the habitable zone of HD 206255 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 206255 b — one full orbit around HD 206255 — lasts 96.0 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.461 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.23).
How Was HD 206255 b Discovered?
HD 206255 b was discovered in 2019 using the radial velocity method, with observations from Las Campanas 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 206255 b?
HD 206255 b is 245.4 light-years (75.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1781. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,319,040 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 206255 b scores 0.17, ranking #4,081 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 206255
HD 206255
- Spectral type
- G5 IV/V
- Surface temperature
- 5,635 K (Sun: 5,772 K)
- Mass
- 1.42 M☉
Planetary System
HD 206255 b is the only planet known to orbit HD 206255 so far.
HD 206255 b — Complete Data
| Mass (best estimate) | 34.20 Earth masses |
|---|---|
| Orbital period | 96.05 days |
| Orbital distance | 0.461 AU |
| Eccentricity | 0.230 |
| Earth Similarity Index | 0.17 |
| Distance from Earth | 245.4 light-years (75.2 parsecs) |
| Constellation | Indus |
| Discovery method | Radial Velocity |
| Discovery facility | Las Campanas Observatory |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-05-20. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 206255 b
Is HD 206255 b habitable?
HD 206255 b is not known to orbit within the habitable zone of HD 206255, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is HD 206255 b?
HD 206255 b is about 245 light-years from Earth in the constellation Indus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,319,040 years to get there.
How long is a year on HD 206255 b?
One orbit around HD 206255 takes 96.0 Earth days.
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