*Prefer Jupiter's trojan asteroids.  (NB. standard exception to WP:PLURAL, article on a group of specific things).  No special capitalisation.  Trojan asteroids, trojoan satelites, trojan regions, etc, are not proper nouns and are not proper names. "Jupiter" is required because there are other trojans for other systems (whether in fact or conceptually).  That astronomers capitalise Trojans is not binding.  "Trojan" in astronomy has become a mere adjective.  It is only a weak allusion to people from Troy; being a trojan satelite is a generic descriptive quality, unlike the "Galilean moons" that are exclusively defined and personally tied to the person Galileo Galilei.