The difference between asteroid and planets is just mass. There are some specific rules that dictate the classifications, but the simplest explanation is just

The difference between asteroid and planets is just mass. There are some specific rules that dictate the classifications, but the simplest explanation is just that asteroids are hunks of space rock and planets are bigger hunks of space rock. The "rogue" in rogue planet means isolated similar to how a "rogue wave" doesn't belong to a pattern of other large waves. A rogue planet is a planet that isn't orbiting a star. There are theoretically also rogue asteroids, but I have never seen that phrased used in that context. That might be because "rogue asteroid" is often used colloquially to describe an difficult to predict asteroid that might hit Earth. Another reason might be is that only asteroids we have ever officially observed are orbiting our sun. Asteroids are so relatively small that it is almost impossible to find one outside our solar system with our current tech. We would basically have to hope that a rogue asteroid just happens to fly through our solar system. ʻOumuamua[1], which was discovered a few years ago was an interstellar object that might fight the definition of rogue asteroid. However there is still a lot of debate whether it was an asteroid, a comet, some other natural space object, or even potentially some artificial object made by intelligent life. That last theory isn't particularly well supported but it is fun to think about. [1] - https://en.wikipedia.org/wiki/%CA%BBOumuamua https://en.wikipedia.org/wiki/%CA%BBOumuamua