An international team of planetary scientists led by astronomers at AOP have found an asteroid trailing behind Mars with a composition very similar to the moon’s. The
asteroid could be an ancient piece of debris, dating back to the gigantic impacts that formed the moon and the other rocky planets in our solar system like Mars and the Earth. The research, which was published in the journal Icarus, also has implications for finding such primordial objects associated with our own planet.
Trojans are a class of asteroid that follows the planets in their orbits as a flock of sheep might follow a shepherd, trapped within gravitational “safe havens” 60 degrees in front of, and behind, the planet (Figure 1). They are of great interest to scientists as they represent leftover material from the formation and early evolution of the solar system. Several thousands of those Trojans exist along the orbit of the giant planet Jupiter. Closer to the Sun, astronomers have so far discovered only a handful of Trojans of Mars, the planet next door to Earth.