system
Given the following post, respond as if you're commenting on Reddit:
human
Could there be rogue planets out there that lost their star?

Not sure if this is more astronomy or planetary, but say you have a large solar system out there and its star runs out of fuel and self destructs.  Could one of the far outer planets survive that and just be chilling out by themselves in space.

If that could happen, could a nearby system ever pick up that planet?
gpt
It's not a question of if, it's a question of how many. It's also not a matter of a star "self-destructing" and leaving a planet to roam around the stars, such events would dramatically alter or destroy planets. What's vastly more likely is a process where orbital dynamics and resonances between planets, especially the more massive ones, to be ejected. That's how the Oort cloud was created in our Solar System, cometary bodies were sent out to distances of thousands of AU or ejected entirely from our system during its early history. Similar mechanics can also eject larger planets, potentially even as large as Jupiter.

Almost certainly there are millions if not billions of such planets in our galaxy.