NASA researchers have proposed a new theory for how Pluto formed its largest moon, Charon. The “kiss-and-capture” process suggests that the two icy bodies collided and merged briefly before separating again.
The theory proposes that Pluto and Charon collided billions of years ago in the Kuiper Belt, a region of icy bodies beyond Neptune’s orbit. Instead of destroying each other, they merged into a single spinning body, which eventually broke apart to form the current Pluto-Charon system.
According to team leader Adeene Denton, the “kiss-and-capture” process is a new way of understanding moon capture in the solar system. The theory suggests that the structural strength of icy bodies played a crucial role in determining whether they merged or remained separate.
Simulations showed that when Pluto and Charon are assumed to have material strength, the brief merger lasts around 10 hours before they separate again. This is significantly shorter than simulations assuming no material strength, which result in a longer-lasting merge.
The researchers believe that the initial collision happened tens of millions of years after the solar system formed, likely billions of years ago. They plan to study how this process may have applied to other large Kuiper Belt Objects with large moons, such as Eris and Dysnomia.
To confirm their formation theory, the team aims to track the long-term tidal evolution of Charon and determine whether it migrated to its current location at around 8 times the width of Pluto away.
Source: https://www.space.com/pluto-charon-kiss-capture