617 Patroclus is a large binary Jupiter trojan asteroid. It is a dark D-type asteroid and a slow rotator, due to the 103-hour orbital period of its two components. It is one of five Jupiter trojan asteroids targeted by the Lucy space probe, and is scheduled for a flyby in 2033.
Hubble Space Telescope image composite of Patroclus and its companion Menoetius, taken in 2018
Plot of the results of the multi-chord stellar occultation by 617 Patroclus and Menoetius
The Jupiter trojans, commonly called trojan asteroids or simply trojans, are a large group of asteroids that share the planet Jupiter's orbit around the Sun. Relative to Jupiter, each trojan librates around one of Jupiter's stable Lagrange points: either L4, existing 60° ahead of the planet in its orbit, or L5, 60° behind. Jupiter trojans are distributed in two elongated, curved regions around these Lagrangian points with an average semi-major axis of about 5.2 AU.
Maximilian Franz Joseph Cornelius Wolf (1890)—the discoverer of the first trojan
A gravitational potential contour plot showing Earth's Lagrangian points; L4 and L5 are ahead (above) and behind (below) the planet, respectively. Jupiter's Lagrangian points are similarly situated in its much larger orbit.
Trojan 624 Hektor (indicated) is similar in brightness to dwarf planet Pluto.
