A group of a few thousand asteroids that travel in roughly
the same orbit as
Jupiter. They occupy the L4 and L5
Lagrange points of the Sun-Jupiter system. As such, they have a 1:1
orbital resonance with Jupiter.
The L4 and L5
Lagrange points are
stable, meaning that any body occupying these points will tend to return if disturbed by a small enough
impulse.
The name
Trojan, refers to the fact that all these asteroids are named after heroes from the
Iliad:
Achilles,
Hector,
Odysseus, etc.