Science and Exploration

Orbital Pathways For A Lunar-Ejecta Origin of the Near-Earth Asteroid Kamo`oalewa

By Keith Cowing
Status Report
May 6, 2023
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Orbital Pathways For A Lunar-Ejecta Origin of the Near-Earth Asteroid Kamo`oalewa
Co-orbital dynamics in the three-body problem and its relation to Kamo‘oalewa’s orbital dynamics. (Top left) The two classes of co-orbitals considered in this work: horseshoe companions oscillate about the L3 Lagrange point, diametrically opposite the planet’s location, and encompass both L4 and L5 Lagrange points; and quasi-satellites orbit outside the planet’s Hill sphere and enclose both the collinear L1 and L2 Lagrange points. Adapted from [16]. (Bottom left) The trace of asteroid (469219) Kamo‘oalewa’s path in Cartesian coordinates in the co-rotating frame; Earth’s position is shown in blue. (Right) Kamo‘oalewa’s semi-major axis a and relative mean longitude ∆λ = λ − λEarth as a function of time, with Horseshoe motion appearing in violet, while quasi-satellite motion is shown in green. Orbital data are from JPL’s Horizons ephemeris service (retrieved on 5 May 2021). — astro-ph.EP

The near-Earth asteroid, Kamo`oalewa (469219), is one of a small number of known quasi-satellites of Earth. Numerical simulations show that it transitions between quasi-satellite and horseshoe orbital states on centennial timescales, maintaining this dynamics over megayears.

The near-Earth asteroid, Kamo`oalewa (469219), is one of a small number of known quasi-satellites of Earth. Numerical simulations show that it transitions between quasi-satellite and horseshoe orbital states on centennial timescales, maintaining this dynamics over megayears.

Its reflectance spectrum suggest a similarity to lunar silicates. Considering its Earth-like orbit and its physical resemblance to lunar surface materials, we explore the hypothesis that it might have originated as a debris-fragment from a meteoroidal impact with the lunar surface.

We carry out numerical simulations of the dynamical evolution of particles launched from different locations on the lunar surface with a range of ejection velocities. As these ejecta escape the Earth-Moon environment and evolve into heliocentric orbits, we find that a small fraction of launch conditions yield outcomes that are compatible with Kamo`oalewa’s dynamical behavior.

The most favored conditions are launch velocities slightly above the escape velocity from the trailing lunar hemisphere.

Jose Daniel Castro-Cisneros, Renu Malhotra, Aaron J. Rosengren
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Space Physics (physics.space-ph)
Cite as: arXiv:2304.14136 [astro-ph.EP] (or arXiv:2304.14136v1 [astro-ph.EP] for this version)
Submission history
From: Jose Daniel Castro-Cisneros
[v1] Thu, 27 Apr 2023 12:30:03 UTC (6,329 KB)
https://arxiv.org/abs/2304.14136

Keith Cowing

SpaceRef co-founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.

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