HD 108874 b
HD 108874 b is a cold gas giant orbiting HD 108874 in the constellation Coma Berenices. It lies about 194 light-years from Earth and was discovered in 2002 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 108874 b in the Habitable Zone?
HD 108874 b orbits inside the conservative habitable zone of HD 108874 — the region where a rocky planet could sustain liquid water on its surface. This makes it one of the most interesting known exoplanets in the search for life.
Habitable zone of HD 108874: 0.748–1.771 AU (conservative: 0.948–1.679 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 108874 b — one full orbit around HD 108874 — lasts 394.5 Earth days, longer than an Earth year. It orbits at an average distance of 1.040 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.13).
How Was HD 108874 b Discovered?
HD 108874 b was discovered in 2002 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 108874 b?
HD 108874 b is 194.1 light-years (59.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1832. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,416,160 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 108874 b scores 0.39, ranking #527 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 108874
HD 108874
- Surface temperature
- 5,600 K (Sun: 5,772 K)
- Mass
- 1.10 M☉
- Radius
- 1.05 R☉
The HD 108874 Planetary System
HD 108874 b is one of 2 known planets in the HD 108874 system. Its siblings:
- HD 108874 c (Cold Gas Giant)
HD 108874 b — Complete Data
| Mass (best estimate) | 451.32 Earth masses |
|---|---|
| Orbital period | 394.48 days |
| Orbital distance | 1.040 AU |
| Eccentricity | 0.130 |
| Earth Similarity Index | 0.39 |
| Distance from Earth | 194.1 light-years (59.5 parsecs) |
| Constellation | Coma Berenices |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2002 |
Data: NASA Exoplanet Archive, last updated 2018-09-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 108874 b
Is HD 108874 b habitable?
HD 108874 b orbits within the habitable zone of HD 108874, the region where liquid water could exist on a planet's surface. It sits in the conservative habitable zone — the most promising region for habitability. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is HD 108874 b?
HD 108874 b is about 194 light-years from Earth in the constellation Coma Berenices. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,416,160 years to get there.
How long is a year on HD 108874 b?
One orbit around HD 108874 takes 394.5 Earth days.
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