A team from the Keck Observatory in Hawaii announced in 2006 that they had measured the density of the binary Trojan asteroid 617 Patroclus as being less than that of water ice, suggesting that the pair, and possibly all the Trojan objects, more closely resemble comets or Kuiper Belt objects in size and composition—water ice with a layer of dust—than than they do the main belt asteroids. (reference: 2.Feb issue of Nature)
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Following Wolf's lead these asteroids were given names associated with the Iliad — in fact, those in the L4 point are named after Greek heroes of the Iliad (the "Greek node" or "Achilles group"), and those at the L5 point are named after the heroes of Troy (the "Trojan node"). Confusingly, the latter group are sometimes called Patroclean asteroids after the most prominent of those, even though Patroclus (the hero) was on the Greek side. However, 617 Patroclus (the asteroid) was the first discovered asteroid at the L5 point, and was named before the Greece/Troy rule was devised. The Greek node also has one "misplaced" asteroid; 624 Hektor.

As the Iliad deals with the events of the Trojan War, the asteroids came to be collectively known as Trojan asteroids. Originally, the term "Trojan" applied only to asteroids sharing Jupiter's orbit; however, planetoidal bodies have been discovered at the Lagrangian points of Mars and Neptune as well, and are also referred to as "Mars Trojans" and "Neptune Trojans" respectively. Also there are Trojan moons around Saturn (Telesto–Tethys–Calypso and Helene–Dione–Polydeuces).

Trojan asteroids in this broader sense may also have played a key role in the formation of the Moon, for which the leading theory states that it formed from the debris of a collision between Earth and a Mars-sized planet very early in the history of the Solar system. Because the collision must have hit Earth sideways and not too hard (otherwise it would have led to full destruction of both objects), it is believed that this hypothetical planet, dubbed Theia, formed from planetesimals that settled into the Lagrangian point L4 of the Sun-Earth system before some cause sent the body veering out of its orbit slowly, onto a path of eventual collision with the young Earth.