HD 222155 b
HD 222155 b is a cold gas giant orbiting HD 222155 in the constellation Andromeda. It lies about 165 light-years from Earth and was discovered in 2011 using the radial velocity method.
Is HD 222155 b in the Habitable Zone?
HD 222155 b orbits beyond the outer edge of the habitable zone of HD 222155. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 222155: 1.358–3.206 AU (conservative: 1.720–3.039 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HD 222155 b — one full orbit around HD 222155 — lasts 3,999.0 Earth days, longer than an Earth year. It orbits at an average distance of 5.140 AU. Its orbit is mildly elliptical (eccentricity 0.16).
How Was HD 222155 b Discovered?
HD 222155 b was discovered in 2011 using the radial velocity method, with observations from Haute-Provence 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 222155 b?
HD 222155 b is 165.1 light-years (50.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1861. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,905,760 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 222155 b scores 0.18, ranking #4,044 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 222155
HD 222155
- Surface temperature
- 5,701 K (Sun: 5,772 K)
- Mass
- 1.21 M☉
- Radius
- 1.85 R☉
Planetary System
HD 222155 b is the only planet known to orbit HD 222155 so far.
HD 222155 b — Complete Data
| Mass (best estimate) | 673.80 Earth masses |
|---|---|
| Orbital period | 3,999.00 days |
| Orbital distance | 5.140 AU |
| Eccentricity | 0.160 |
| Earth Similarity Index | 0.18 |
| Distance from Earth | 165.1 light-years (50.6 parsecs) |
| Constellation | Andromeda |
| Discovery method | Radial Velocity |
| Discovery facility | Haute-Provence Observatory |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2018-09-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 222155 b
Is HD 222155 b habitable?
No — HD 222155 b orbits outside the habitable zone of HD 222155 and is likely too cold for liquid water on its surface.
How far away is HD 222155 b?
HD 222155 b is about 165 light-years from Earth in the constellation Andromeda. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,905,760 years to get there.
How long is a year on HD 222155 b?
One orbit around HD 222155 takes 3,999.0 Earth days.
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