Shape and spin axis determination of the Tianwen-2 target asteroid (469219) Kamo'oalewa from lightcurve inversion

Fuente: arXiv
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Autores principales: Bonamico, Roberto, Hanuš, Josef, Delbo, Marco
Formato: Preprint
Publicado: 2026
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author Bonamico, Roberto
Hanuš, Josef
Delbo, Marco
author_facet Bonamico, Roberto
Hanuš, Josef
Delbo, Marco
contents Near-Earth asteroid (469219) Kamo'oalewa is an Earth quasi-satellite, temporarily trapped in a 1:1 orbital resonance with our planet. Despite its dynamical relevance and the hypothesis that it may be a lunar ejecta fragment, its physical properties are still poorly constrained. In particular, no reliable models of its shape and spin state have been published so far. The scientific interest in this object is further enhanced by its selection as the primary target of the Chinese Tianwen-2 mission, which aims to rendezvous with this asteroid and return samples of it to Earth. The aim of this work is to determine the shape and spin axis orientation of Kamo'oalewa by means of photometric telescope observations and lightcurve inversion. We analyzed lightcurves obtained during several apparitions using the well-established algorithm, based on convex shape modeling. We derived a convex shape model and estimated the spin pole orientation. In the preferred solution, the pole is located at ecliptic coordinates λ, β = (126,-16) degrees, with a sidereal rotation period of P~0.465 h. Conclusions. Our results provide the first direct constraints on the rotational state and morphology of Kamo'oalewa, information of key importance in preparation for the upcoming Tianwen-2 sample-return mission.
format Preprint
id arxiv_https___arxiv_org_abs_2604_26734
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Shape and spin axis determination of the Tianwen-2 target asteroid (469219) Kamo'oalewa from lightcurve inversion
Bonamico, Roberto
Hanuš, Josef
Delbo, Marco
Earth and Planetary Astrophysics
Near-Earth asteroid (469219) Kamo'oalewa is an Earth quasi-satellite, temporarily trapped in a 1:1 orbital resonance with our planet. Despite its dynamical relevance and the hypothesis that it may be a lunar ejecta fragment, its physical properties are still poorly constrained. In particular, no reliable models of its shape and spin state have been published so far. The scientific interest in this object is further enhanced by its selection as the primary target of the Chinese Tianwen-2 mission, which aims to rendezvous with this asteroid and return samples of it to Earth. The aim of this work is to determine the shape and spin axis orientation of Kamo'oalewa by means of photometric telescope observations and lightcurve inversion. We analyzed lightcurves obtained during several apparitions using the well-established algorithm, based on convex shape modeling. We derived a convex shape model and estimated the spin pole orientation. In the preferred solution, the pole is located at ecliptic coordinates λ, β = (126,-16) degrees, with a sidereal rotation period of P~0.465 h. Conclusions. Our results provide the first direct constraints on the rotational state and morphology of Kamo'oalewa, information of key importance in preparation for the upcoming Tianwen-2 sample-return mission.
title Shape and spin axis determination of the Tianwen-2 target asteroid (469219) Kamo'oalewa from lightcurve inversion
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2604.26734