HD 59686 A b
HD 59686 A b is a cold gas giant orbiting the K2 III star HD 59686 A in the constellation Gemini. It lies about 291 light-years from Earth and was discovered in 2016 using the radial velocity method.
Is HD 59686 A b in the Habitable Zone?
HD 59686 A b orbits inside the inner edge of the habitable zone of HD 59686 A. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 59686 A: 6.820–16.729 AU (conservative: 8.639–15.861 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HD 59686 A b — one full orbit around HD 59686 A — lasts 299.4 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 1.086 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.05).
How Was HD 59686 A b Discovered?
HD 59686 A b was discovered in 2016 using the radial velocity method, with observations from Lick 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 59686 A b?
HD 59686 A b is 291.2 light-years (89.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1735. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,125,120 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 59686 A b scores 0.09, ranking #4,531 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 59686 A
HD 59686 A b belongs to a system of 2 stars; it orbits HD 59686 A.
HD 59686 A
- Spectral type
- K2 III
- Surface temperature
- 4,658 K (Sun: 5,772 K)
- Mass
- 1.90 M☉
- Radius
- 13.20 R☉
- Age
- 1.7 billion years (Sun: 4.6)
Planetary System
HD 59686 A b is the only planet known to orbit HD 59686 A so far.
HD 59686 A b — Complete Data
| Mass (best estimate) | 2,199.38 Earth masses |
|---|---|
| Orbital period | 299.36 days |
| Orbital distance | 1.086 AU |
| Eccentricity | 0.050 |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 291.2 light-years (89.3 parsecs) |
| Constellation | Gemini |
| Discovery method | Radial Velocity |
| Discovery facility | Lick Observatory |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-08-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 59686 A b
Is HD 59686 A b habitable?
No — HD 59686 A b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 59686 A b?
HD 59686 A b is about 291 light-years from Earth in the constellation Gemini. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,125,120 years to get there.
How long is a year on HD 59686 A b?
One orbit around HD 59686 A takes 299.4 Earth days.
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