This schematic shows the five Lagrangian regions around Neptune's orbit. Six Neptune Trojans are known in the leading L4 region and now one is known in the trailing L5 region. The discovery demonstrates that Neptune hosts similar clouds of Trojans at either of two points 60° away from the planet where the gravitational forces of the planet and the Sun combine to lock the asteroids into a stable, synchronized orbit. The Neptune Trojans likely outnumber the main belt of asteroids between Mars and Jupiter.
Subaru Telescope's copyright