HD 13808 b
HD 13808 b is a Neptune-like planet orbiting the K2 V star HD 13808 in the constellation Eridanus. It lies about 92 light-years from Earth and was discovered in 2021 using the radial velocity method.
Is HD 13808 b in the Habitable Zone?
HD 13808 b orbits inside the inner edge of the habitable zone of HD 13808. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 13808: 0.464–1.120 AU (conservative: 0.587–1.062 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 13808 b — one full orbit around HD 13808 — lasts 14.2 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.105 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.07).
How Was HD 13808 b Discovered?
HD 13808 b was discovered in 2021 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 13808 b?
HD 13808 b is 92.1 light-years (28.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1934. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,620,960 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 13808 b scores 0.23, ranking #3,472 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 13808
HD 13808
- Spectral type
- K2 V
- Surface temperature
- 5,035 K (Sun: 5,772 K)
- Mass
- 0.77 M☉
- Radius
- 0.78 R☉
- Age
- 7.2 billion years (Sun: 4.6)
The HD 13808 Planetary System
HD 13808 b is one of 2 known planets in the HD 13808 system. Its siblings:
- HD 13808 c (Super Earth)
HD 13808 b — Complete Data
| Mass (best estimate) | 11.20 Earth masses |
|---|---|
| Orbital period | 14.18 days |
| Orbital distance | 0.105 AU |
| Eccentricity | 0.071 |
| Earth Similarity Index | 0.23 |
| Distance from Earth | 92.1 light-years (28.2 parsecs) |
| Constellation | Eridanus |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-02-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 13808 b
Is HD 13808 b habitable?
No — HD 13808 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 13808 b?
HD 13808 b is about 92 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,620,960 years to get there.
How long is a year on HD 13808 b?
One orbit around HD 13808 takes 14.2 Earth days — short enough that 26 of its years would fit into one Earth year.
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