"We were definitely surprised by the 'kiss' part of kiss-and-capture. There hasn't really been a kind of impact before where the two bodies only temporarily merge before re-separating!" ...

Charon is the largest of Pluto’s five moons, with a radius more than half that of Pluto itself, but the question of how it came to orbit Pluto has puzzled astronomers. Read more Why the big bang ...

In this scenario, Charon would have remained relatively intact, retaining its core and most of its mantle, and would be as old as Pluto, whose radius (1,200 kilometers) is twice as large.