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Hauptverfasser: Kurosaki, Kenji, Arakawa, Masahiko
Format: Preprint
Veröffentlicht: 2026
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Online-Zugang:https://arxiv.org/abs/2605.11819
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author Kurosaki, Kenji
Arakawa, Masahiko
author_facet Kurosaki, Kenji
Arakawa, Masahiko
contents Rubble-pile asteroids can form through the self-gravitational reaccumulation of fragments produced during large-scale collisions. To investigate how differentiated bodies are disrupted and how iron-rich rubble piles may form, we performed smoothed particle hydrodynamics simulations of impacts between differentiated asteroids with molten or solidified interiors. Our results show that catastrophic disruption produces a sheet-like structure in which core and mantle materials are stretched and subsequently fragment under self-gravity. The resulting fragments exhibit nearly identical iron-rock mass ratios, indicating that catastrophic disruption naturally generates numerous compositionally similar fragments. The largest remnant formed in such events is therefore an iron-rich rubble pile assembled from these mixed fragments, whereas remnants formed through mantle stripping retain a layered structure with an iron core and rocky mantle. We further find that fragment production is sensitive to material strength and the equation of state: mantle strength reduces the number of small fragments, while core strength suppresses catastrophic disruption when the core is solid. These results imply that iron-rich rubble-pile asteroids can form only when the iron core is molten. Our findings provide a unified framework for the formation of metal-rich asteroids such as (16) Psyche and the (22) Kalliope system, and offer predictions for the surface and internal structure that the NASA Psyche mission may test.
format Preprint
id arxiv_https___arxiv_org_abs_2605_11819
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Reaccumulation process after a catastrophic disruption event on a differentiated asteroid
Kurosaki, Kenji
Arakawa, Masahiko
Earth and Planetary Astrophysics
Rubble-pile asteroids can form through the self-gravitational reaccumulation of fragments produced during large-scale collisions. To investigate how differentiated bodies are disrupted and how iron-rich rubble piles may form, we performed smoothed particle hydrodynamics simulations of impacts between differentiated asteroids with molten or solidified interiors. Our results show that catastrophic disruption produces a sheet-like structure in which core and mantle materials are stretched and subsequently fragment under self-gravity. The resulting fragments exhibit nearly identical iron-rock mass ratios, indicating that catastrophic disruption naturally generates numerous compositionally similar fragments. The largest remnant formed in such events is therefore an iron-rich rubble pile assembled from these mixed fragments, whereas remnants formed through mantle stripping retain a layered structure with an iron core and rocky mantle. We further find that fragment production is sensitive to material strength and the equation of state: mantle strength reduces the number of small fragments, while core strength suppresses catastrophic disruption when the core is solid. These results imply that iron-rich rubble-pile asteroids can form only when the iron core is molten. Our findings provide a unified framework for the formation of metal-rich asteroids such as (16) Psyche and the (22) Kalliope system, and offer predictions for the surface and internal structure that the NASA Psyche mission may test.
title Reaccumulation process after a catastrophic disruption event on a differentiated asteroid
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2605.11819