HD 208487 b
HD 208487 b is a cold gas giant orbiting the G2 V star HD 208487 in the constellation Grus. It lies about 147 light-years from Earth and was discovered in 2004 using the radial velocity method.
Is HD 208487 b in the Habitable Zone?
HD 208487 b orbits inside the inner edge of the habitable zone of HD 208487. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 208487: 0.960–2.244 AU (conservative: 1.216–2.127 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 208487 b — one full orbit around HD 208487 — lasts 129.4 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.530 AU — comparable to the inner Solar System. Its orbit is highly elliptical (eccentricity 0.37), swinging dramatically closer to and farther from its star.
How Was HD 208487 b Discovered?
HD 208487 b was discovered in 2004 using the radial velocity method, with observations from Anglo-Australian Telescope.
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 208487 b?
HD 208487 b is 147.2 light-years (45.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1879. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,590,720 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 208487 b scores 0.19, ranking #3,927 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 208487
HD 208487
- Spectral type
- G2 V
- Surface temperature
- 6,134 K (Sun: 5,772 K)
- Mass
- 1.15 M☉
- Radius
- 1.16 R☉
- Luminosity
- 1.7100 L☉
- Age
- 2.0 billion years (Sun: 4.6)
Planetary System
HD 208487 b is the only planet known to orbit HD 208487 so far.
HD 208487 b — Complete Data
| Mass (best estimate) | 146.20 Earth masses |
|---|---|
| Orbital period | 129.36 days |
| Orbital distance | 0.530 AU |
| Eccentricity | 0.370 |
| Earth Similarity Index | 0.19 |
| Distance from Earth | 147.2 light-years (45.1 parsecs) |
| Constellation | Grus |
| Discovery method | Radial Velocity |
| Discovery facility | Anglo-Australian Telescope |
| Discovery year | 2004 |
Data: NASA Exoplanet Archive, last updated 2026-02-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 208487 b
Is HD 208487 b habitable?
No — HD 208487 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 208487 b?
HD 208487 b is about 147 light-years from Earth in the constellation Grus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,590,720 years to get there.
How long is a year on HD 208487 b?
One orbit around HD 208487 takes 129.4 Earth days.
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