HD 86226 c
HD 86226 c is a super-Earth orbiting the G1 V star HD 86226 in the constellation Hydra. It lies about 149 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is HD 86226 c?
HD 86226 c has a radius of 2.16 times that of Earth. Its mass is 7.3 times that of Earth, giving it a density of 3.97 g/cm³ — between that of rocky and gaseous planets.
Is HD 86226 c in the Habitable Zone?
HD 86226 c orbits inside the inner edge of the habitable zone of HD 86226. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 86226: 0.811–1.907 AU (conservative: 1.027–1.808 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 86226 c
The equilibrium temperature of HD 86226 c is about 1,311 K (1,038 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on HD 86226 c — one full orbit around HD 86226 — lasts 3.98 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.049 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.08).
How Was HD 86226 c Discovered?
HD 86226 c was discovered in 2020 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
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 86226 c?
HD 86226 c is 149.0 light-years (45.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1877. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,622,400 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 86226 c scores 0.25, ranking #3,117 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 86226
HD 86226
- Spectral type
- G1 V
- Surface temperature
- 5,863 K (Sun: 5,772 K)
- Mass
- 1.02 M☉
- Radius
- 1.05 R☉
- Luminosity
- 1.1800 L☉
- Age
- 4.6 billion years (Sun: 4.6)
The HD 86226 Planetary System
HD 86226 c is one of 2 known planets in the HD 86226 system. Its siblings:
- HD 86226 b (Cold Gas Giant)
HD 86226 c — Complete Data
| Radius | 2.160 Earth radii (0.193 Jupiter radii) |
|---|---|
| Mass | 7.25 Earth masses (0.023 Jupiter masses) |
| Density | 3.97 g/cm³ (Earth: 5.51) |
| Orbital period | 3.98 days |
| Orbital distance | 0.049 AU |
| Eccentricity | 0.075 |
| Equilibrium temperature | 1,311 K (1,038 °C) |
| Earth Similarity Index | 0.25 |
| Distance from Earth | 149.0 light-years (45.7 parsecs) |
| Constellation | Hydra |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-08-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 86226 c
Is HD 86226 c habitable?
No — HD 86226 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 86226 c?
HD 86226 c is about 149 light-years from Earth in the constellation Hydra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,622,400 years to get there.
How big is HD 86226 c compared to Earth?
HD 86226 c has 2.16 times the radius of Earth and about 7.3 times its mass.
How long is a year on HD 86226 c?
One orbit around HD 86226 takes 4.0 Earth days — short enough that 92 of its years would fit into one Earth year.
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