HD 99706 b
HD 99706 b is a cold gas giant orbiting HD 99706 in the constellation Ursa Major. It lies about 478 light-years from Earth and was discovered in 2011 using the radial velocity method.
Is HD 99706 b in the Habitable Zone?
HD 99706 b orbits inside the inner edge of the habitable zone of HD 99706. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 99706: 3.081–7.491 AU (conservative: 3.903–7.102 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 99706 b — one full orbit around HD 99706 — lasts 841.0 Earth days, longer than an Earth year. It orbits at an average distance of 1.980 AU. Its orbit is mildly elliptical (eccentricity 0.25).
How Was HD 99706 b Discovered?
HD 99706 b was discovered in 2011 using the radial velocity method, with observations from W. M. Keck 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 99706 b?
HD 99706 b is 478.1 light-years (146.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1548. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 8,414,560 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 99706 b scores 0.25, ranking #3,007 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 99706
HD 99706
- Surface temperature
- 4,862 K (Sun: 5,772 K)
- Mass
- 1.46 M☉
- Radius
- 5.52 R☉
The HD 99706 Planetary System
HD 99706 b is one of 2 known planets in the HD 99706 system. Its siblings:
- HD 99706 c (Cold Gas Giant)
HD 99706 b — Complete Data
| Mass (best estimate) | 390.93 Earth masses |
|---|---|
| Orbital period | 841.00 days |
| Orbital distance | 1.980 AU |
| Eccentricity | 0.250 |
| Earth Similarity Index | 0.25 |
| Distance from Earth | 478.1 light-years (146.6 parsecs) |
| Constellation | Ursa Major |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2018-12-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 99706 b
Is HD 99706 b habitable?
No — HD 99706 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 99706 b?
HD 99706 b is about 478 light-years from Earth in the constellation Ursa Major. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 8,414,560 years to get there.
How long is a year on HD 99706 b?
One orbit around HD 99706 takes 841.0 Earth days.
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