A whole new Earth: astronomers have found the densest planet of its kind in the universe.

Astronomers have discovered a new planetary system consisting of a gas giant and an Earth-sized planet. Both worlds orbit a star similar to the Sun. The so-called super-Earth has an exceptionally short orbital period and is the densest planet in its class among all known planets. The research findings, published in Scientific Reports, provide new insights into how planets form and evolve over time under the most extreme conditions, according to Phys.

Scientists have identified two new exoplanets orbiting a Sun-like star named K2-360, which is located 750 light-years away from us. Farther from the star is the gas giant K2-360 c, which has a mass approximately 15 times that of Earth. The orbital period of this planet is just 9.8 Earth days. Astronomers have not yet been able to determine the precise size of the planet.

Another Earth with Lead-like Density

The so-called super-Earth, designated K2-360 b, has generated significant interest. This rocky planet is larger than Earth but smaller than Neptune. K2-360 b has an orbital period of only 21 Earth hours, making it a rocky planet with an extraordinarily short rotation period around its star. Its mass is about 7.7 times that of Earth.

Consequently, this world is the densest known planet outside our solar system, with an orbital period of less than one Earth day. According to scientists, K2-360 b is as dense as lead, with a mass nearly 8 times that of Earth compressed into a sphere slightly larger than our planet.

Evolution of the Densest Planet with a Very Short Orbit

Researchers believe that this super-Earth has become so dense because it represents a core that has lost its outer layers from a larger planet. This occurred due to its proximity to its star, whose radiation has stripped away the outer layers.

Astronomers think that K2-360 b consists of a rocky mantle surrounding a massive iron core, which constitutes about 48% of the planet's total mass. The surface of this world is likely covered by molten magma.

According to scientists, studying such planets helps us understand how Earth-like planets form and evolve under various, including very extreme, conditions in the Milky Way. Planets with extraordinarily short orbital periods are rare.

The authors of the study suggest that K2-360 b likely followed a different evolutionary path compared to similar planets, considering the presence of the gas giant K2-360 c nearby. While many planets located close to their stars ended up there due to interactions with the protoplanetary disk, K2-360 b likely migrated due to gravitational interactions with its neighboring planet.