Review of Jupiter-Trojan asteroids research

Jupiter-Trojan asteroids, as fossils of planet formation, orbiting the Sun in Jupiter's stable Lagrange points, provide a unique and critical insight into planetary origins, the sources of volatiles and organics on the terrestrial planets, and the evolution of the planetary system as a whole. To present, Jupiter-Trojan asteroids have only been observed through remote spectroscopic measurements using ground-based telescopes or space telescopes, and they remain one of the most enigmatic groups of celestial bodies. In the past decade, significant advances in understanding their physical and spectral properties have been made, and there has been a revolution in thinking about the origin and evolution of Trojans. Fine-grained silicates that appear to be similar to cometary silicates have gradually replaced water ice and organics as a significant component of the surface composition of Trojan asteroids, and a color bimodality may indicate distinct compositional groups among the Trojans. Whereas Trojans had traditionally been thought to have formed near 5 AU, a new paradigm in which the Trojans formed in the proto-Kuiper Belt, were scattered inward, and then captured in the Trojan swarms as a result of resonant interactions of the giant planets has developed. There are significant differences between the currently determined physical properties of Trojans and Kuiper Belt objects. These differences may be indicative of surface modification attributable to the inward migration of the objects that became the Trojans. The upcoming Lucy mission will provide a unique opportunity to conduct close-up exploration of these enigmatic small celestial bodies, potentially yielding evidence important for unraveling the mysteries surrounding the origin and evolution of Jupiter-Trojan asteroids. This paper provides a comprehensive overview of the observational history, physical and spectral properties, material composition, and formation and evolution of Jupiter-Trojan asteroids, as well as an introduction to the goals and objectives of the Lucy mission. This study provides support for potential future deep space exploration missions that may have the capacity of exploring asteroids.