Oort Cloud ecology

Springer Link (Chiba Institute of Technology)

Abstract

Aims. We investigated the influence of cluster environments on asteroids, with particular attention to captured material. Methods. Using numerical methods, we simulated a sub-virial fractally distributed star-forming region and a virialised Plummer-distributed star-forming region. We initialised both models with a virial radius of 0.5 pc and 150 stars. Stellar populations and their corresponding planetary systems are identical between cluster models. Stars initially hosted 500 asteroids, and those with mass M* ≤ 2.0 M⊙ were also orbited by one to eight planets. We integrated clusters until 30 Myr. Results. The sub-virial fractal cluster exhibits richer dynamics, with asteroids and planets more frequently acquiring high eccentricities and inclinations, along with a larger fraction of captured and rogue objects. Additionally, this cluster configuration has its extreme trans-Neptunian object and Sednoid analogues occupying regions of phase-space in semi-major axis, eccentricity, and inclination commonly frequented by captured asteroids. Although the virialised Plummer model can produce such objects, it is less dynamically active, and the vast majority of asteroids occupying these regions are native rather than captured. Lastly, neither model efficiently forms an Oort Cloud, indicating that Oort Cloud assembly is strongly suppressed in both dynamically hot and more quiescent clusters.

Authors 2

1. Erwan Hochart Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory , University of Leiden , Niels Bohrweg 2 , 2333 CA Leiden , the Netherlands

2. Simon Portegies Zwart Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory , University of Leiden , Niels Bohrweg 2 , 2333 CA Leiden , the Netherlands