Dynamical histories of active and inactive Centaurs

Yu-Chi Cheng^1*, Wing-Huen Ip¹

¹Institute of Astronomy, National Central University, Taoyuan City, Taiwan

* Presenter:Yu-Chi Cheng, email:yccheng@astro.ncu.edu.tw

Centaurs are evolutionary transient objects between the Jupiter-Family Comets and the Trans-Neptunian Objects, which occupy the orbit between Jupiter and Neptune. They have a median dynamical lifetime of several Myr and various dynamical histories indicating a complex thermal exposure history, which may be a hint to explain their observational appearances: Centaurs can be divided into two identical groups according to their observational appearance, dynamic and physical properties. The active Centaurs are grouped in a relatively high orbital inclination (>20⁰), bluer surface color (N. Peixinho et al. 2012), and following the random-walk orbital migration (B. L. Bailey & R. Malhotra 2009). Those physical properties have also been observed in the Trans-Neptunian objects, which might be an important clue to the planet migration scenario.

Recent observation powered by the James Webb Space Telescope reveals the chemical diversity of the outer solar system icy bodies via infrared spectra that can be classified into three major taxonomical groups: H₂O-type (bowls), CO₂-type (double-dips), and organics-type (cliffs), which are indicative of the environment of their formation region (M. N. De Pr´a et al. 2025; B. J. Holler et al. 2025). Interestingly, J. Licandro et al. (2025) reported that the surface texture of Centaur objects seems responsible for their thermal exposure history. We launched a series of N-body numerical simulations to study the dynamical properties of active and inactive Centaurs. For searching the connection between the dynamical evolution history and the chemical properties as we observed in the present day.

Keywords: Comet dynamics, Short period comets, Solar system evolution, Centaur group