K2-72 e
K2-72 e is a small, potentially rocky planet located approximately 217 light-years away in the constellation Aquarius. It is the outermost of four planets orbiting a cool red dwarf star.
Key Physical Characteristics
- Planet Type: Terrestrial (rocky) world.
- Size: It is very similar to Earth, with a radius about 1.29 times that of our planet.
- Orbit: It completes one orbit around its star every 24 Earth days.
- The Star: K2-72 is an M-dwarf star. Because it is much smaller and cooler than our Sun, its habitable zone is much closer to the stellar surface.
Habitability & Environment
In Lisa Kaltenegger’s research, K2-72 e is a significant candidate for a “temperate” Earth-like world:
- Location: It sits firmly within the Habitable Zone, where temperatures could allow for liquid water on the surface.
- Energy Intake: It receives about 1.1 to 1.2 times the starlight that Earth gets from the Sun. This puts it in a climate category very similar to Earth’s, perhaps slightly warmer.
- Atmosphere: Given its size and the relatively “quiet” nature of its host star, scientists believe it has a good chance of having retained a stable atmosphere over billions of years.
Scientific Significance
- Small Planet Focus: While many discovered exoplanets are massive “Super-Earths,” K2-72 e is exciting because its size is closer to Earth’s, making it a better analog for our own home.
- Multi-Planet Laboratory: It is part of a system with three other planets (b, c, and d), all of which are much hotter. This allows Kaltenegger and her team to compare how rocky planets at different distances from the same star evolve.
- Transit Discovery: It was discovered by the Kepler Space Telescope during its “K2” mission. Because it transits its star, it is a candidate for future atmospheric studies to look for water vapor.
Published @ March 24, 2026 9:32 am