HD 220689 b
HD 220689 b is a cold gas giant orbiting HD 220689 in the constellation Aquarius. It lies about 153 light-years from Earth and was discovered in 2012 using the radial velocity method.
Is HD 220689 b in the Habitable Zone?
HD 220689 b orbits beyond the outer edge of the habitable zone of HD 220689. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 220689: 0.834–1.959 AU (conservative: 1.057–1.857 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on HD 220689 b — one full orbit around HD 220689 — lasts 2,266.4 Earth days, longer than an Earth year. It orbits at an average distance of 3.396 AU. Its orbit is mildly elliptical (eccentricity 0.05).
How Was HD 220689 b Discovered?
HD 220689 b was discovered in 2012 using the radial velocity method, with observations from La Silla 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 220689 b?
HD 220689 b is 152.9 light-years (46.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1874. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,691,040 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 220689 b scores 0.16, ranking #4,117 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 220689
HD 220689
- Surface temperature
- 5,921 K (Sun: 5,772 K)
- Mass
- 1.02 M☉
- Radius
- 1.07 R☉
- Age
- 4.6 billion years (Sun: 4.6)
Planetary System
HD 220689 b is the only planet known to orbit HD 220689 so far.
HD 220689 b — Complete Data
| Mass (best estimate) | 355.33 Earth masses |
|---|---|
| Orbital period | 2,266.40 days |
| Orbital distance | 3.396 AU |
| Eccentricity | 0.054 |
| Earth Similarity Index | 0.16 |
| Distance from Earth | 152.9 light-years (46.9 parsecs) |
| Constellation | Aquarius |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2012 |
Data: NASA Exoplanet Archive, last updated 2019-06-24. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 220689 b
Is HD 220689 b habitable?
No — HD 220689 b orbits outside the habitable zone of HD 220689 and is likely too cold for liquid water on its surface.
How far away is HD 220689 b?
HD 220689 b is about 153 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,691,040 years to get there.
How long is a year on HD 220689 b?
One orbit around HD 220689 takes 2,266.4 Earth days.
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