K2-24 b
K2-24 b is a Neptune-like planet orbiting K2-24 in the constellation Scorpius. It lies about 556 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is K2-24 b?
K2-24 b has a radius of 5.40 times that of Earth. Its mass is 19.0 times that of Earth, giving it a density of 0.64 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is K2-24 b in the Habitable Zone?
The position of K2-24 b relative to the habitable zone of K2-24 cannot be precisely determined from the available orbital data.
Habitable zone of K2-24: 0.833–1.970 AU (conservative: 1.055–1.868 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on K2-24 b — one full orbit around K2-24 — lasts 20.9 Earth days, shorter than Mercury's 88-day year. Its orbit is mildly elliptical (eccentricity 0.06).
How Was K2-24 b Discovered?
K2-24 b 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 K2-24 b?
K2-24 b is 556.3 light-years (170.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1470. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,790,880 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. K2-24 b scores 0.16, ranking #4,140 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-24
K2-24
- Surface temperature
- 5,625 K (Sun: 5,772 K)
- Mass
- 1.07 M☉
- Radius
- 1.16 R☉
The K2-24 Planetary System
K2-24 b is one of 2 known planets in the K2-24 system. Its siblings:
- K2-24 c (Cold Gas Giant)
K2-24 b — Complete Data
| Radius | 5.400 Earth radii (0.482 Jupiter radii) |
|---|---|
| Mass | 19.00 Earth masses (0.060 Jupiter masses) |
| Density | 0.64 g/cm³ (Earth: 5.51) |
| Orbital period | 20.89 days |
| Eccentricity | 0.060 |
| Earth Similarity Index | 0.16 |
| Distance from Earth | 556.3 light-years (170.6 parsecs) |
| Constellation | Scorpius |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2018-12-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-24 b
Is K2-24 b habitable?
K2-24 b is not known to orbit within the habitable zone of K2-24, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is K2-24 b?
K2-24 b is about 556 light-years from Earth in the constellation Scorpius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,790,880 years to get there.
How big is K2-24 b compared to Earth?
K2-24 b has 5.40 times the radius of Earth and about 19.0 times its mass.
How long is a year on K2-24 b?
One orbit around K2-24 takes 20.9 Earth days — short enough that 17 of its years would fit into one Earth year.
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