K2-417 b
K2-417 b is a super-Earth orbiting the M V star K2-417 in the constellation Aquarius. It lies about 307 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is K2-417 b?
K2-417 b has a radius of 3.31 times that of Earth. Its mass is 699 times that of Earth.
Is K2-417 b in the Habitable Zone?
K2-417 b orbits inside the inner edge of the habitable zone of K2-417. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-417: 0.204–0.520 AU (conservative: 0.258–0.493 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-417 b
The equilibrium temperature of K2-417 b is about 558 K (285 °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.
Orbit and Year Length
A year on K2-417 b — one full orbit around K2-417 — lasts 6.54 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.063 AU — closer to its star than Mercury is to the Sun.
How Was K2-417 b Discovered?
K2-417 b was discovered in 2023 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 K2-417 b?
K2-417 b is 306.7 light-years (94.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1720. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,397,920 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. K2-417 b scores 0.27, ranking #2,591 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-417
K2-417
- Spectral type
- M V
- Surface temperature
- 3,861 K (Sun: 5,772 K)
- Mass
- 0.57 M☉
- Radius
- 0.58 R☉
- Luminosity
- 0.0628 L☉
Planetary System
K2-417 b is the only planet known to orbit K2-417 so far.
K2-417 b — Complete Data
| Radius | 3.310 Earth radii (0.295 Jupiter radii) |
|---|---|
| Mass | 699.22 Earth masses (2.200 Jupiter masses) |
| Orbital period | 6.54 days |
| Orbital distance | 0.063 AU |
| Equilibrium temperature | 558 K (285 °C) |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 306.7 light-years (94.0 parsecs) |
| Constellation | Aquarius |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-07-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-417 b
Is K2-417 b habitable?
No — K2-417 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-417 b?
K2-417 b is about 307 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,397,920 years to get there.
How big is K2-417 b compared to Earth?
K2-417 b has 3.31 times the radius of Earth and about 699 times its mass.
How long is a year on K2-417 b?
One orbit around K2-417 takes 6.5 Earth days — short enough that 56 of its years would fit into one Earth year.
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