HD 3651 b
HD 3651 b is a cold gas giant orbiting HD 3651 in the constellation Pisces. It lies about 36 light-years from Earth and was discovered in 2003 using the radial velocity method.
Is HD 3651 b in the Habitable Zone?
The position of HD 3651 b relative to the habitable zone of HD 3651 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 3651 b — one full orbit around HD 3651 — lasts 62.3 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.295 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.65), swinging dramatically closer to and farther from its star.
How Was HD 3651 b Discovered?
HD 3651 b was discovered in 2003 using the radial velocity method, with observations from Multiple Observatories.
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 3651 b?
HD 3651 b is 36.3 light-years (11.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1990. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 638,880 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 3651 b scores 0.20, ranking #3,873 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 3651
HD 3651
- Surface temperature
- 5,221 K (Sun: 5,772 K)
- Mass
- 0.80 M☉
Planetary System
HD 3651 b is the only planet known to orbit HD 3651 so far.
HD 3651 b — Complete Data
| Mass (best estimate) | 72.47 Earth masses |
|---|---|
| Orbital period | 62.25 days |
| Orbital distance | 0.295 AU |
| Eccentricity | 0.645 |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 36.3 light-years (11.1 parsecs) |
| Constellation | Pisces |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2003 |
Data: NASA Exoplanet Archive, last updated 2019-03-11. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 3651 b
Is HD 3651 b habitable?
HD 3651 b is not known to orbit within the habitable zone of HD 3651, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 3651 b?
HD 3651 b is about 36 light-years from Earth in the constellation Pisces. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 638,880 years to get there.
How long is a year on HD 3651 b?
One orbit around HD 3651 takes 62.3 Earth days.
Explore HD 3651 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.
