An international team of scientists has found a fascinating new planetary system around a star similar to our sun.
The system, located about 750 light-years from Earth, contains two planets, including one of the densest rocky planets ever discovered.
This breakthrough, published in Scientific Reports on November 8, offers new clues about how planets form and survive in extreme environments.
The system is called K2-360 and includes:
- K2-360 b: A rocky planet known as a “super-Earth,” 1.6 times the size of Earth but with a mass 7.7 times greater. It is so dense that its composition is comparable to lead. It completes one orbit around its star in just 21 hours, making it an ultra-short period planet.
- K2-360 c: A larger planet that is at least 15 times the mass of Earth and takes 9.8 days to orbit the star. Scientists cannot see it directly because it doesn’t pass in front of its star, but they know it exists due to its gravitational effects on the star.
“K2-360 b is incredible,” said John Livingston, a lead researcher from the Astrobiology Center in Tokyo. “It’s like squeezing nearly eight Earth masses into a planet just slightly bigger than our own.”
The discovery was made using data from NASA’s K2 mission, which first spotted K2-360 b in 2016. Ground-based telescopes later confirmed its existence and detected the second planet.
K2-360 b’s extreme density suggests it could be the leftover core of a much larger planet that lost its outer layers due to intense radiation from its nearby star. This rare glimpse into planetary evolution provides evidence of what might happen to planets orbiting very close to their stars over billions of years.
The outer planet, K2-360 c, adds more intrigue. Its gravitational pull might have pushed the smaller inner planet closer to the star. Scientists believe this could have happened through a process called high-eccentricity migration, where the planet’s path first becomes very stretched out before settling into a circular orbit due to the star’s tidal forces.
K2-360 b likely has a structure similar to Earth, with a massive iron core making up nearly half its mass and a rocky mantle. The extreme heat from the star might even keep its surface covered in molten rock.
Studying planets like K2-360 b can help scientists understand how rocky worlds form and survive under harsh conditions. “This system is a perfect laboratory for exploring the origins of planets in extreme environments,” Livingston added.
This discovery highlights the incredible variety of planets in the galaxy and brings us one step closer to understanding the complex processes that shape planetary systems.
Source: National Institutes of Natural Sciences.
