A new space rock has been found that devotedly travels around with Mars as it orbits the Sun, bringing the total number of such „groupies“ to four. The asteroid, called 2007 NS2, was discovered by astronomers at the La Sagra Observatory in southern Spain on July 14, 2007. Based on its brightness, it is estimated to be about one kilometre across. It follows Mars in its orbit, occupying the L5 spot, which lags the Red Planet by 60° as it moves around the Sun. It shares L5 with two other objects, while a fourth object orbits 60° ahead of Mars at the L4 point. Objects that wander into the L4 and L5 points of a planet tend to be confined there by the combined gravity of the planet and the Sun. Mars is one of just three planets known to have such „Trojan“ objects in its orbit. About 2200 Trojans are known to accompany Jupiter in its orbit, and a handful have been discovered in Neptune’s orbit as well.
List Of Martian Trojans

The Lagrange Points