HD 30856 b
HD 30856 b is a cold gas giant orbiting HD 30856 in the constellation Eridanus. It lies about 428 light-years from Earth and was discovered in 2011 using the radial velocity method.
Is HD 30856 b in the Habitable Zone?
HD 30856 b orbits inside the inner edge of the habitable zone of HD 30856. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 30856: 2.486–6.035 AU (conservative: 3.148–5.722 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 30856 b — one full orbit around HD 30856 — lasts 847.0 Earth days, longer than an Earth year. It orbits at an average distance of 1.850 AU. Its orbit is mildly elliptical (eccentricity 0.06).
How Was HD 30856 b Discovered?
HD 30856 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 30856 b?
HD 30856 b is 427.9 light-years (131.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1599. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,531,040 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 30856 b scores 0.30, ranking #1,384 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 30856
HD 30856 b belongs to a system of 2 stars; it orbits HD 30856.
HD 30856
- Surface temperature
- 4,895 K (Sun: 5,772 K)
- Mass
- 1.17 M☉
- Radius
- 4.40 R☉
Planetary System
HD 30856 b is the only planet known to orbit HD 30856 so far.
HD 30856 b — Complete Data
| Mass (best estimate) | 491.68 Earth masses |
|---|---|
| Orbital period | 847.00 days |
| Orbital distance | 1.850 AU |
| Eccentricity | 0.061 |
| Earth Similarity Index | 0.30 |
| Distance from Earth | 427.9 light-years (131.2 parsecs) |
| Constellation | Eridanus |
| 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 30856 b
Is HD 30856 b habitable?
No — HD 30856 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 30856 b?
HD 30856 b is about 428 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,531,040 years to get there.
How long is a year on HD 30856 b?
One orbit around HD 30856 takes 847.0 Earth days.
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