HD 219828 b
HD 219828 b is a Neptune-like planet orbiting HD 219828 in the constellation Pegasus. It lies about 239 light-years from Earth and was discovered in 2007 using the radial velocity method.
Is HD 219828 b in the Habitable Zone?
The position of HD 219828 b relative to the habitable zone of HD 219828 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 219828 b — one full orbit around HD 219828 — lasts 3.83 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.049 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.09).
How Was HD 219828 b Discovered?
HD 219828 b was discovered in 2007 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 219828 b?
HD 219828 b is 238.5 light-years (73.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1788. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,197,600 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 219828 b scores 0.16, ranking #4,139 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 219828
HD 219828
- Mass
- 1.04 M☉
The HD 219828 Planetary System
HD 219828 b is one of 2 known planets in the HD 219828 system. Its siblings:
HD 219828 b — Complete Data
| Mass (best estimate) | 19.07 Earth masses |
|---|---|
| Orbital period | 3.83 days |
| Orbital distance | 0.049 AU |
| Eccentricity | 0.091 |
| Earth Similarity Index | 0.16 |
| Distance from Earth | 238.5 light-years (73.1 parsecs) |
| Constellation | Pegasus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2007 |
Data: NASA Exoplanet Archive, last updated 2023-06-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 219828 b
Is HD 219828 b habitable?
HD 219828 b is not known to orbit within the habitable zone of HD 219828, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is HD 219828 b?
HD 219828 b is about 239 light-years from Earth in the constellation Pegasus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,197,600 years to get there.
How long is a year on HD 219828 b?
One orbit around HD 219828 takes 3.8 Earth days — short enough that 95 of its years would fit into one Earth year.
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