HD 102956 b
HD 102956 b is a hot Jupiter orbiting HD 102956 in the constellation Ursa Major. It lies about 398 light-years from Earth and was discovered in 2010 using the radial velocity method.
Is HD 102956 b in the Habitable Zone?
HD 102956 b orbits inside the inner edge of the habitable zone of HD 102956. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 102956: 2.655–6.422 AU (conservative: 3.362–6.089 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 102956 b — one full orbit around HD 102956 — lasts 6.49 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.081 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.037).
How Was HD 102956 b Discovered?
HD 102956 b was discovered in 2010 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 102956 b?
HD 102956 b is 397.6 light-years (121.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1629. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 6,997,760 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 102956 b scores 0.07, ranking #5,040 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 102956
HD 102956 b belongs to a system of 2 stars; it orbits HD 102956.
HD 102956
- Surface temperature
- 4,985 K (Sun: 5,772 K)
- Mass
- 1.66 M☉
- Radius
- 4.55 R☉
Planetary System
HD 102956 b is the only planet known to orbit HD 102956 so far.
HD 102956 b — Complete Data
| Mass (best estimate) | 305.12 Earth masses |
|---|---|
| Orbital period | 6.49 days |
| Orbital distance | 0.081 AU |
| Eccentricity | 0.037 |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 397.6 light-years (121.9 parsecs) |
| Constellation | Ursa Major |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2018-12-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 102956 b
Is HD 102956 b habitable?
No — HD 102956 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 102956 b?
HD 102956 b is about 398 light-years from Earth in the constellation Ursa Major. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 6,997,760 years to get there.
How long is a year on HD 102956 b?
One orbit around HD 102956 takes 6.5 Earth days — short enough that 56 of its years would fit into one Earth year.
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