HD 13908 b
HD 13908 b is a cold gas giant orbiting the F8 V star HD 13908 in the constellation Cassiopeia. It lies about 260 light-years from Earth and was discovered in 2013 using the radial velocity method.
Is HD 13908 b in the Habitable Zone?
HD 13908 b orbits inside the inner edge of the habitable zone of HD 13908. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 13908: 1.458–3.398 AU (conservative: 1.847–3.222 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on HD 13908 b — one full orbit around HD 13908 — lasts 19.4 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.154 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.020).
How Was HD 13908 b Discovered?
HD 13908 b was discovered in 2013 using the radial velocity method, with observations from Haute-Provence 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 13908 b?
HD 13908 b is 259.5 light-years (79.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1767. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,567,200 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 13908 b scores 0.07, ranking #4,917 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 13908
HD 13908
- Spectral type
- F8 V
- Surface temperature
- 6,255 K (Sun: 5,772 K)
- Mass
- 1.29 M☉
- Radius
- 1.67 R☉
- Luminosity
- 3.9994 L☉
- Age
- 2.9 billion years (Sun: 4.6)
The HD 13908 Planetary System
HD 13908 b is one of 2 known planets in the HD 13908 system. Its siblings:
- HD 13908 c (Cold Gas Giant)
HD 13908 b — Complete Data
| Mass (best estimate) | 274.91 Earth masses |
|---|---|
| Orbital period | 19.38 days |
| Orbital distance | 0.154 AU |
| Eccentricity | 0.020 |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 259.5 light-years (79.6 parsecs) |
| Constellation | Cassiopeia |
| Discovery method | Radial Velocity |
| Discovery facility | Haute-Provence Observatory |
| Discovery year | 2013 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 13908 b
Is HD 13908 b habitable?
No — HD 13908 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 13908 b?
HD 13908 b is about 260 light-years from Earth in the constellation Cassiopeia. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,567,200 years to get there.
How long is a year on HD 13908 b?
One orbit around HD 13908 takes 19.4 Earth days — short enough that 19 of its years would fit into one Earth year.
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