Passage: Planetary migration occurs when a planet or other stellar satellite interacts with a disk of gas or planetesimals, resulting in the alteration of the satellite's orbital parameters, especially its semi-major axis.  Planetary migration is the most likely explanation for hot Jupiters: exoplanets with Jovian masses but orbits of only a few days.  The generally accepted theory of planet formation from a protoplanetary disk predicts such planets cannot form so close to their stars, as there is insufficient mass at such small radii and the temperature is too high to allow the formation of rocky or icy planetesimals.

Question: What is it called when a planet or object is moved from its normal orbit?
Planetary migration