A team of American astronomers has proposed a new simulation to explain the configuration of Pluto and its massive moon Charon, shedding light on their origin story. The researchers used a hydrodynamic model to describe the collision between the Moon and Earth in 2001, but this time they took into account the solidity of both bodies.
The “Kiss and Capture” scenario suggests that Pluto and proto-Charon were once composed of 85% rock and 15% ice. At an angle of 45 degrees and a speed of 1 kilometer per second, the two objects collided, causing Charon to begin rotating around Pluto within just a few dozen hours. Over time, Charon moved away from its original orbit and settled into its current circular path.
In this scenario, Charon retained its core and most of its mantle, making it as old as Pluto. The impact also produced debris that could have contributed to the formation of Pluto’s four other moons. This new understanding provides a more complete picture of the complex history of our solar system’s outer reaches.
Source: https://www.lemonde.fr/en/science/article/2025/01/06/image-of-the-week-pluto-and-charon-s-fascinating-embrace_6736758_10.html