Is it illegal to own a planet?

In the realm of cryptocurrency and finance, we often grapple with complex legal issues surrounding digital assets and their ownership. However, this question seems to traverse a whole new frontier: is it illegal to own a planet? This inquiry begs for clarification, as traditionally, planets are considered part of the vast expanse of space, outside the jurisdiction of any single nation's laws. Nevertheless, as space exploration and colonization become increasingly feasible, such questions are gaining relevance. Does international law govern planetary ownership? Are there treaties or conventions that establish parameters for such claims? Or is the concept of owning a planet simply a fanciful one, with no practical legal implications?