Official rule text
15.2 STEP 2— The player who controls the planet that is being reinforcements instead of on the capturing player’s faction bombarded chooses and destroys one of their ground forces on sheet; the capturing player places a fighter or infantry token that planet for each hit result the bombardment roll produced. from the supply on their faction sheet instead. a If a player has to assign more hits than that player has
View official source
Source: Twilight Imperium: Fourth Edition - Living Rules Reference: Prophecy of Kings
Expansion: Prophecy of Kings
Version: 2.0
Reference: Rule 15.2