HD 25171 b
HD 25171 b is a cold gas giant orbiting HD 25171 in the constellation Reticulum. It lies about 181 light-years from Earth and was discovered in 2010 using the radial velocity method.
Is HD 25171 b in the Habitable Zone?
HD 25171 b orbits beyond the outer edge of the habitable zone of HD 25171. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 25171: 1.016–2.373 AU (conservative: 1.286–2.250 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 25171 b — one full orbit around HD 25171 — lasts 1,802.3 Earth days, longer than an Earth year. It orbits at an average distance of 2.971 AU. Its orbit is nearly circular (eccentricity 0.042).
How Was HD 25171 b Discovered?
HD 25171 b was discovered in 2010 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 25171 b?
HD 25171 b is 181.4 light-years (55.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1845. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,192,640 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 25171 b scores 0.24, ranking #3,411 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 25171
HD 25171 b belongs to a system of 2 stars; it orbits HD 25171.
HD 25171
- Surface temperature
- 6,125 K (Sun: 5,772 K)
- Mass
- 1.08 M☉
- Radius
- 1.23 R☉
- Age
- 4.8 billion years (Sun: 4.6)
Planetary System
HD 25171 b is the only planet known to orbit HD 25171 so far.
HD 25171 b — Complete Data
| Mass (best estimate) | 290.81 Earth masses |
|---|---|
| Orbital period | 1,802.29 days |
| Orbital distance | 2.971 AU |
| Eccentricity | 0.042 |
| Earth Similarity Index | 0.24 |
| Distance from Earth | 181.4 light-years (55.6 parsecs) |
| Constellation | Reticulum |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2019-06-24. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 25171 b
Is HD 25171 b habitable?
No — HD 25171 b orbits outside the habitable zone of HD 25171 and is likely too cold for liquid water on its surface.
How far away is HD 25171 b?
HD 25171 b is about 181 light-years from Earth in the constellation Reticulum. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,192,640 years to get there.
How long is a year on HD 25171 b?
One orbit around HD 25171 takes 1,802.3 Earth days.
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