20461 dioretsa4/25/2023 ![]() Under certain circumstances, they can also be classified as either Main Belt asteroids (MBAs) or inner planet crossers, such as near-Earth asteroids (NEAs e.g. According to the Minor Planet Center (MPC) classification, most of these retrograde asteroids belong to either the Centaur or Trans-Neptunian object (TNO) populations. Since the discovery of asteroid (20461) Dioretsa in 1999 (MPC: 48396), the results of systematic observations and analysis show that the list of asteroids in retrograde orbits ( i > 90°) is steadily increasing. Methods: numerical, celestial mechanics, minor planets, asteroids: general 1 INTRODUCTION To explain this more precisely, the same model based on new physical parameters, determined from future observations, will be required. Additionally, the changes in orbital elements, caused by Yarkovsky forces, appear to depend on the integration direction. Because of the presence of this effect, it is possible that the median lifetimes of these objects are extended. We found that the Yarkovsky effect can have a significant influence on the lifetimes of asteroids in retrograde orbits. In addition, we studied the possible influence of the Yarkovsky effect on our results. A large portion of the objects studied displayed smaller values of τ (τ ∼ 1 Myr). We found three objects whose retrograde orbits were stable with a dynamical lifetime τ ∼ 10–100 Myr. Finally, we estimated the median lifetimes of 25 asteroids. We also used a gravitational model for comparison. Next, we collected the available thermal properties of our objects and we used them in an enhanced dynamical model with Yarkovsky forces. These swarms were then input into long-term numerical integrations, and the orbital elements were averaged. We first used orbit determination and cloning to produce swarms of test particles. We studied their dynamical evolution in the past and future for ☑00 Myr (☑ Gyr for three particular cases). We selected 25 asteroids with the best-determined orbital elements. The aim of our study was to estimate the dynamical lifetimes of these bodies using the latest observational data, including astrometry and physical properties. The population of known minor bodies in retrograde orbits ( i > 90°) that are classified as asteroids is still growing.
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