>>10875478I'm kinda confused about what you're asking, so I'll try to answer on more general terms.
Anything from a single atom to the biggest black hole in existence can be rouge in space. Rouge meaning that it's not in any stable orbit, like around a star - but rather just traveling through space.
An orbit is just a path (that can be calculated with pretty simple mathematics when it only comes to an orbit between two objects, otherwise look at n-body problem) of object or objects around a barycentre; that's the spot in space where the gravitational pull of all the objects within a (for example solar) system is the same.
If a rouge object comes within the right distance of a strong enough gravitational pull and it has just the right amount of velocity not to crash into the other object and not to just skimp past it, then it'll get 'captured' into an orbit.
