Speaker: Prof. Liyong ZHOU(Nanjing University)
Jun. 8, 2023
3 pm GMT+8
Meeting ID: 827 8580 9805
In the restricted three-body problem consisting of the Sun, a planet and a small body, two triangular equilibrium points known as the 4th and 5th Lagrange points are stable for all planets in the Solar System. Small bodies found around these two equilibrium points are called Trojan asteroids (or Trojans) after the first such groups of small bodies detected in the orbit of Jupiter. For a given planet in the Solar System, gravitational perturbations from other planets and various non-gravitational perturbations may lead to very complex motions of Trojans, and even instability of orbits. Meanwhile, Trojan asteroids are generally believed to have formed elsewhere before entering the region around the triangular equilibrium points, so the existence of Trojans and their distribution in space could be an important clue to the history of formation and evolution of the Solar System in the early stage. In this report I will present our findings on the orbital stability of Trojans of the planets Venus, Earth, Mars, Uranus and Neptune. All the main dynamical mechanisms that influence their orbital stabilities will be depicted, and the implications on the evolutionary history of planetary orbits and suggestions for the future astronomical surveys for Trojans, will be discussed.
About the speaker
Dr. Liyong Zhou received his BSc (Physics, 1995) and PhD (Astronomy, 2000) from Nanjing University, China. He then joined the Department of Astronomy at Nanjing University. During some interruptions in this term he worked as a postdoctoral fellow in Tuorla Observatory, Finland and a visiting scholar in University of Sao Paulo, Brazil. He became a professor in School of Astronomy and Space Science, Nanjing University in 2010. His research interests include the dynamics of small bodies in the Solar System, resonances in planetary system, and general nonlinear dynamics. In recent years, he focuses on the dynamics of Trojan asteroids and non-gravitational effects such as the Yarkovsky effect and YORP effect.