HD 220773 b
HD 220773 b is a cold gas giant orbiting the F9 star HD 220773 in the constellation Pegasus. It lies about 165 light-years from Earth and was discovered in 2011 using the radial velocity method.
Is HD 220773 b in the Habitable Zone?
The position of HD 220773 b relative to the habitable zone of HD 220773 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 220773 b — one full orbit around HD 220773 — lasts 3,724.7 Earth days, longer than an Earth year. It orbits at an average distance of 4.940 AU. Its orbit is highly elliptical (eccentricity 0.51), swinging dramatically closer to and farther from its star.
How Was HD 220773 b Discovered?
HD 220773 b was discovered in 2011 using the radial velocity method, with observations from McDonald 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 220773 b?
HD 220773 b is 164.7 light-years (50.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1862. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,898,720 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 220773 b scores 0.20, ranking #3,915 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 220773
HD 220773
- Spectral type
- F9
- Surface temperature
- 5,940 K (Sun: 5,772 K)
- Mass
- 1.16 M☉
- Age
- 4.4 billion years (Sun: 4.6)
Planetary System
HD 220773 b is the only planet known to orbit HD 220773 so far.
HD 220773 b — Complete Data
| Mass (best estimate) | 460.80 Earth masses |
|---|---|
| Orbital period | 3,724.70 days |
| Orbital distance | 4.940 AU |
| Eccentricity | 0.510 |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 164.7 light-years (50.5 parsecs) |
| Constellation | Pegasus |
| Discovery method | Radial Velocity |
| Discovery facility | McDonald Observatory |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2019-01-28. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 220773 b
Is HD 220773 b habitable?
HD 220773 b is not known to orbit within the habitable zone of HD 220773, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 220773 b?
HD 220773 b is about 165 light-years from Earth in the constellation Pegasus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,898,720 years to get there.
How long is a year on HD 220773 b?
One orbit around HD 220773 takes 3,724.7 Earth days.
Explore HD 220773 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
