What is Trojan asteroid?
[[File:Lagrange very massive.svg|250px|thumb|Trojan points are the points labelled L4 and L5, highlighted in red, on the orbital path of the secondary object (blue), around the primary object (yellow).]] [[File:InnerSolarSystem-en.png|250px|thumb|Trojan asteroids of [[Jupiter]] (coloured green) in front of and behind the planet along its orbital path. Also shown is the [[asteroid belt]] between the orbits of [[Mars]] and Jupiter (white), and the [[Hilda family]] of asteroids (brown).]] Trojan objects orbit 60° ahead (L4) or behind (L5) a more massive object. Both are in orbit around an even more massive central object. The best known example are the asteroids that orbit ahead or behind [[Jupiter]] around the [[Sun]]. Trojan objects do not orbit exactly at one of either [[Lagrange point]]s, but do remain close to it, appearing to slowly orbit it. The largest group of [[asteroid]]s known to move around the [[Sun]] are those with the [[planet]] [[Jupiter (planet)|Jupiter]]. There are two groups of Jovian Trojans, one group on each side of Jupiter. == History == === Theory === In 1772 the French mathematician and astronomer [[Joseph-Louis Lagrange]] identified two spots in a planet's orbit which were [[gravitation]]ally [[Stability|stable]]. If put there, an object would stay there.<ref>They are not actually stationary, but each moves in an orbit within its Lagrange area.</ref> Lagrange predicted the existence of a group of small bodies in each of the two stable points in Jupiter’s orbit. The term originally referred to the Trojan asteroids orbiting around [[Jupiter]]'s Lagrangian points, which are by convention named after figures from the [[Trojan War]] of [[Greek mythology]]. By convention, the asteroids orbiting Jupiter's L<sub>4</sub> point are named after the heroes from the Greek side of the war, while those at L<sub>5</sub> are from the Trojan side. The two exceptions, the Greek-themed [[617 Patroclus]] and the Trojan-themed [[624 Hektor]], were actually assigned to the wrong sides.<ref>{{cite journal | t