An International team of astronomers led by researcher Toni Santana-Ros, from the University of Alicante and the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), has confirmed the existence of the second Earth Trojan asteroid known to date, the 2020 XL5, after a decade of search. The results of the study have been published in the journal Nature Communications.
All celestial objects that roam around our solar system feel the gravitational influence of all the other massive bodies that build it, including the Sun and the planets. If we consider only the Earth-Sun system, Newton's laws of gravity state that there are five points where all the forces that act upon an object located at that point cancel each other out. These regions are called Lagrangian points, and they are areas of great stability. Earth Trojan asteroids are small bodies that orbit around the L4 or L5 Lagrangian points of the Sun-Earth system.
These results confirm that 2020 XL5 is the second transient Earth Trojan asteroid known to date, and everything indicates it will remain Trojan —that is, it will be located at the Lagrangian point— for four thousand years, thus it is qualified as transient. The researchers have provided an estimation of the object bulk size (around one kilometer in diameter, larger than the Earth Trojan asteroid known to date, the 2010 TK7, which was 0.3 kilometres in diameter), and have made a study of the impulse a rocket needs to reach the asteroid from Earth.
Although Trojan asteroids have been known to exist for decades in other planets such as Venus, Mars, Jupiter, Uranus and Neptune, it was not until 2011 that the first Earth Trojan asteroid was found. The astronomers have described many observational strategies for the detection of new Earth Trojans. "There have been many previous attempts to find Earth Trojans, including in situ surveys such as the search within the L4 region, carried out by the NASA OSIRIS-Rex spacecraft, or the search within the L5
