HD 22496 b
HD 22496 b is a super-Earth orbiting HD 22496 in the constellation Horologium. It lies about 44 light-years from Earth and was discovered in 2021 using the radial velocity method.
Is HD 22496 b in the Habitable Zone?
HD 22496 b orbits inside the inner edge of the habitable zone of HD 22496. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 22496: 0.208–0.516 AU (conservative: 0.263–0.489 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 22496 b
The equilibrium temperature of HD 22496 b is about 573 K (300 °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 26.00 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HD 22496 b — one full orbit around HD 22496 — lasts 5.09 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.051 AU — closer to its star than Mercury is to the Sun.
How Was HD 22496 b Discovered?
HD 22496 b was discovered in 2021 using the radial velocity method, with observations from Paranal 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 22496 b?
HD 22496 b is 44.3 light-years (13.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1982. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 779,680 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 22496 b scores 0.29, ranking #1,672 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 22496
HD 22496
- Surface temperature
- 4,385 K (Sun: 5,772 K)
- Mass
- 0.68 M☉
- Radius
- 0.67 R☉
- Luminosity
- 0.0670 L☉
Planetary System
HD 22496 b is the only planet known to orbit HD 22496 so far.
HD 22496 b — Complete Data
| Mass (best estimate) | 5.57 Earth masses |
|---|---|
| Orbital period | 5.09 days |
| Orbital distance | 0.051 AU |
| Equilibrium temperature | 573 K (300 °C) |
| Stellar irradiation | 26.00× Earth |
| Earth Similarity Index | 0.29 |
| Distance from Earth | 44.3 light-years (13.6 parsecs) |
| Constellation | Horologium |
| Discovery method | Radial Velocity |
| Discovery facility | Paranal Observatory |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-09-20. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 22496 b
Is HD 22496 b habitable?
No — HD 22496 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 22496 b?
HD 22496 b is about 44 light-years from Earth in the constellation Horologium. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 779,680 years to get there.
How long is a year on HD 22496 b?
One orbit around HD 22496 takes 5.1 Earth days — short enough that 72 of its years would fit into one Earth year.
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