HD 3167 c
HD 3167 c is a mini-Neptune orbiting HD 3167 in the constellation Pisces. It lies about 154 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is HD 3167 c?
HD 3167 c has a radius of 3.00 times that of Earth. Its mass is 11.1 times that of Earth, giving it a density of 2.11 g/cm³ — between that of rocky and gaseous planets.
Is HD 3167 c in the Habitable Zone?
HD 3167 c orbits inside the inner edge of the habitable zone of HD 3167. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 3167: 0.564–1.350 AU (conservative: 0.714–1.280 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 3167 c
The equilibrium temperature of HD 3167 c is about 564 K (291 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 16.90 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HD 3167 c — one full orbit around HD 3167 — lasts 29.8 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.178 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.06).
How Was HD 3167 c Discovered?
HD 3167 c was discovered in 2016 using the transit method, with observations from K2.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is HD 3167 c?
HD 3167 c is 154.2 light-years (47.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1872. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,713,920 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 3167 c scores 0.28, ranking #2,300 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 3167
HD 3167
- Surface temperature
- 5,261 K (Sun: 5,772 K)
- Mass
- 0.84 M☉
- Radius
- 0.88 R☉
- Age
- 7.8 billion years (Sun: 4.6)
The HD 3167 Planetary System
HD 3167 c is one of 4 known planets in the HD 3167 system. Its siblings:
HD 3167 c — Complete Data
| Radius | 3.000 Earth radii (0.268 Jupiter radii) |
|---|---|
| Mass | 11.13 Earth masses (0.035 Jupiter masses) |
| Density | 2.11 g/cm³ (Earth: 5.51) |
| Orbital period | 29.85 days |
| Orbital distance | 0.178 AU |
| Eccentricity | 0.060 |
| Equilibrium temperature | 564 K (291 °C) |
| Stellar irradiation | 16.90× Earth |
| Earth Similarity Index | 0.28 |
| Distance from Earth | 154.2 light-years (47.3 parsecs) |
| Constellation | Pisces |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2023-04-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 3167 c
Is HD 3167 c habitable?
No — HD 3167 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 3167 c?
HD 3167 c is about 154 light-years from Earth in the constellation Pisces. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,713,920 years to get there.
How big is HD 3167 c compared to Earth?
HD 3167 c has 3.00 times the radius of Earth and about 11.1 times its mass.
How long is a year on HD 3167 c?
One orbit around HD 3167 takes 29.8 Earth days — short enough that 12 of its years would fit into one Earth year.
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