HD 156411 b
HD 156411 b is a cold gas giant orbiting the F8 IV/V star HD 156411 in the constellation Ara. It lies about 186 light-years from Earth and was discovered in 2009 using the radial velocity method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
Is HD 156411 b in the Habitable Zone?
HD 156411 b orbits within the optimistic habitable zone of HD 156411 — the broader region where liquid water might be possible under favorable atmospheric conditions.
Habitable zone of HD 156411: 1.728–4.059 AU (conservative: 2.189–3.849 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 156411 b — one full orbit around HD 156411 — lasts 842.2 Earth days, longer than an Earth year. It orbits at an average distance of 1.880 AU. Its orbit is mildly elliptical (eccentricity 0.22).
How Was HD 156411 b Discovered?
HD 156411 b was discovered in 2009 using the radial velocity method, with observations from La Silla 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 156411 b?
HD 156411 b is 185.5 light-years (56.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1841. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,264,800 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 156411 b scores 0.37, ranking #640 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 156411
HD 156411
- Spectral type
- F8 IV/V
- Surface temperature
- 5,900 K (Sun: 5,772 K)
- Mass
- 1.25 M☉
- Radius
- 2.16 R☉
- Luminosity
- 5.3827 L☉
Planetary System
HD 156411 b is the only planet known to orbit HD 156411 so far.
HD 156411 b — Complete Data
| Mass (best estimate) | 235.18 Earth masses |
|---|---|
| Orbital period | 842.20 days |
| Orbital distance | 1.880 AU |
| Eccentricity | 0.220 |
| Earth Similarity Index | 0.37 |
| Distance from Earth | 185.5 light-years (56.9 parsecs) |
| Constellation | Ara |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2009 |
Data: NASA Exoplanet Archive, last updated 2014-06-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 156411 b
Is HD 156411 b habitable?
HD 156411 b orbits within the habitable zone of HD 156411, the region where liquid water could exist on a planet's surface. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is HD 156411 b?
HD 156411 b is about 186 light-years from Earth in the constellation Ara. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,264,800 years to get there.
How long is a year on HD 156411 b?
One orbit around HD 156411 takes 842.2 Earth days.
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