Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model

This paper investigates the mass shifts of asteroid (99942) Apophis during its 2029 close encounter with Earth, using the contact dynamics method, a type of discrete element method. Unlike previous analyses, we model the asteroid as a contact binary body with the addition of granules between the bod...

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Main Authors: Hai-Shuo Wang, Paul Sánchez, D.J. Scheeres
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Planetary Science Journal
Subjects:
Online Access:https://doi.org/10.3847/PSJ/adf73f
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author Hai-Shuo Wang
Paul Sánchez
D.J. Scheeres
author_facet Hai-Shuo Wang
Paul Sánchez
D.J. Scheeres
author_sort Hai-Shuo Wang
collection DOAJ
description This paper investigates the mass shifts of asteroid (99942) Apophis during its 2029 close encounter with Earth, using the contact dynamics method, a type of discrete element method. Unlike previous analyses, we model the asteroid as a contact binary body with the addition of granules between the body’s components. To account for uncertainties in Apophis’ shape, we create eight multibody models, with a particular focus on a contact binary asteroid model featuring boulders concentrated in its neck region. Our simulations show that the inclusion of boulders, whether distributed across the surface or concentrated in the neck region, facilitates internal mass shifts, with minimal differences between models, indicating that boulder placement has little effect on the magnitude of the mass shifts. In polyhedral models, angularity dominates over friction and orientation. Spherical models are more sensitive to friction and orientation than shape. Both show minimal sensitivity to tensile strength. While we can find considerable shifts in the system for some parameter values, for values we consider more realistic, we find only modest deformation of the components and motion of surface material, on par with previous simulations. A critical stability threshold is identified at a neck size ratio of α  ≈ 0.4, below which contact binary asteroids become highly vulnerable to external perturbations and tend to reconfigure into more stable shapes.
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spelling doaj-art-7333a68927a642f2bf69c0b9870a5b392025-08-26T06:24:24ZengIOP PublishingThe Planetary Science Journal2632-33382025-01-016820210.3847/PSJ/adf73fSimulating the (99942) Apophis Earth Flyby Using a Contact Binary ModelHai-Shuo Wang0https://orcid.org/0000-0002-7633-5363Paul Sánchez1https://orcid.org/0000-0003-3610-5480D.J. Scheeres2https://orcid.org/0000-0003-0558-3842University of Colorado Boulder , 3775 Discovery Drive, Boulder, CO 80303, USAUniversity of Colorado Boulder , 3775 Discovery Drive, Boulder, CO 80303, USAUniversity of Colorado Boulder , 3775 Discovery Drive, Boulder, CO 80303, USAThis paper investigates the mass shifts of asteroid (99942) Apophis during its 2029 close encounter with Earth, using the contact dynamics method, a type of discrete element method. Unlike previous analyses, we model the asteroid as a contact binary body with the addition of granules between the body’s components. To account for uncertainties in Apophis’ shape, we create eight multibody models, with a particular focus on a contact binary asteroid model featuring boulders concentrated in its neck region. Our simulations show that the inclusion of boulders, whether distributed across the surface or concentrated in the neck region, facilitates internal mass shifts, with minimal differences between models, indicating that boulder placement has little effect on the magnitude of the mass shifts. In polyhedral models, angularity dominates over friction and orientation. Spherical models are more sensitive to friction and orientation than shape. Both show minimal sensitivity to tensile strength. While we can find considerable shifts in the system for some parameter values, for values we consider more realistic, we find only modest deformation of the components and motion of surface material, on par with previous simulations. A critical stability threshold is identified at a neck size ratio of α  ≈ 0.4, below which contact binary asteroids become highly vulnerable to external perturbations and tend to reconfigure into more stable shapes.https://doi.org/10.3847/PSJ/adf73fAsteroid dynamicsAsteroidsAsteroid surfaces
spellingShingle Hai-Shuo Wang
Paul Sánchez
D.J. Scheeres
Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model
The Planetary Science Journal
Asteroid dynamics
Asteroids
Asteroid surfaces
title Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model
title_full Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model
title_fullStr Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model
title_full_unstemmed Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model
title_short Simulating the (99942) Apophis Earth Flyby Using a Contact Binary Model
title_sort simulating the 99942 apophis earth flyby using a contact binary model
topic Asteroid dynamics
Asteroids
Asteroid surfaces
url https://doi.org/10.3847/PSJ/adf73f
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