(This question is in reference to this post)
I would read that magazine.
But yeah, they are most definitely a thing. I’ve covered them here before.
When solar systems are forming, and young planets condense out of gases and debris, their orbits are not always stable. Either because of collisions (like the one that created our moon) or extreme elliptical orbits at the distant edges of their star system, they can be catapulted out of regular orbits and sentenced to a life among the darkness.
It would look something like this: