Oort Cloud Ecology - IV. Exchanging Asteroids
Erwan Hochart, Simon Portegies Zwart
TLDR
This study simulates star-forming regions to show how cluster dynamics influence asteroid capture and Oort Cloud formation, finding sub-virial clusters are more dynamic.
Key contributions
- Sub-virial fractal clusters exhibit richer dynamics, leading to more captured and rogue asteroids/planets.
- Extreme trans-Neptunian objects in sub-virial clusters often originate from captured asteroids.
- Virialized Plummer clusters produce fewer captured objects, with most asteroids being native.
- Neither cluster type efficiently forms an Oort Cloud, indicating suppression in both dynamic and quiescent environments.
Why it matters
Understanding asteroid dynamics in star clusters is crucial for tracing the origins of solar system objects. This research highlights how initial cluster conditions profoundly impact the distribution and capture of asteroids, offering insights into early planetary system evolution and Oort Cloud formation challenges.
Original Abstract
Aims. Investigate the influence of cluster environments on asteroids, with special attention towards captured material. Methods. Using numerical methods, a sub-virial fractally distributed star-forming region and a virialised Plummer distributed star-forming region are simulated. Both models are initialised with a virial radius of 0.5pc and 150 stars. Stellar populations and their corresponding planetary systems are identical between cluster models. Stars initially host 500 asteroids and those with mass M_* <= 2.0 MSun are also orbited by 1 - 8 planets. Clusters are integrated 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 occupy 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, by being less dynamically active, the vast majority of asteroids occupying these regions are native rather than captured. Lastly, neither model efficiently form an Oort Cloud, indicating that Oort Cloud assembly is strongly suppressed in both dynamically hot and more quiescent cluster
📬 Weekly AI Paper Digest
Get the top 10 AI/ML arXiv papers from the week — summarized, scored, and delivered to your inbox every Monday.