K2-43 c
K2-43 c is a mini-Neptune orbiting K2-43 in the constellation Leo. It lies about 595 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is K2-43 c?
K2-43 c has a radius of 2.42 times that of Earth.
Is K2-43 c in the Habitable Zone?
The position of K2-43 c relative to the habitable zone of K2-43 cannot be precisely determined from the available orbital data.
Habitable zone of K2-43: 0.195–0.497 AU (conservative: 0.247–0.471 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 ›
Temperature on K2-43 c
The equilibrium temperature of K2-43 c is about 1,094 K (821 °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 K2-43 c — one full orbit around K2-43 — lasts 2.20 Earth days, shorter than Mercury's 88-day year.
How Was K2-43 c Discovered?
K2-43 c was discovered in 2019 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 K2-43 c?
K2-43 c is 595.4 light-years (182.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1431. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 10,479,040 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. K2-43 c scores 0.25, ranking #3,096 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-43
K2-43
- Surface temperature
- 3,841 K (Sun: 5,772 K)
- Mass
- 0.57 M☉
- Radius
- 0.54 R☉
The K2-43 Planetary System
K2-43 c is one of 2 known planets in the K2-43 system. Its siblings:
- K2-43 b (Neptune-like)
K2-43 c — Complete Data
| Radius | 2.420 Earth radii (0.216 Jupiter radii) |
|---|---|
| Orbital period | 2.20 days |
| Equilibrium temperature | 1,094 K (821 °C) |
| Earth Similarity Index | 0.25 |
| Distance from Earth | 595.4 light-years (182.5 parsecs) |
| Constellation | Leo |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-08-09. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-43 c
Is K2-43 c habitable?
K2-43 c is not known to orbit within the habitable zone of K2-43, and as a mini-Neptune it is an unlikely candidate for life as we know it.
How far away is K2-43 c?
K2-43 c is about 595 light-years from Earth in the constellation Leo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 10,479,040 years to get there.
How big is K2-43 c compared to Earth?
K2-43 c has 2.42 times the radius of Earth.
How long is a year on K2-43 c?
One orbit around K2-43 takes 2.2 Earth days — short enough that 166 of its years would fit into one Earth year.
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