{
  "abstract": "(469219) Kamo`oalewa is the most stable Earth quasi-satellite and the target of China's Tianwen-2 asteroid sample return mission. Due to its small size, fast rotation, and the limited observing geometry accessible from the ground, many physical properties of Kamo`oalewa remain poorly constrained, including the rotational state and shape. We obtained three epochs of high-cadence, high signal-to-noise photometric lightcurves of Kamo`oalewa with the Gemini North Telescope from 2026 April to May, supplemented by one lightcurve from the Lowell Discovery Telescope in 2026 May. Our analysis suggests that Kamo`oalewa is in a non-principal-axis rotation with an elongated shape. Four possible solutions exist, including a long-axis mode (LAM) solution and a short-axis mode (SAM) solution, as well as their corresponding mirrored angular momentum directions. The most preferable solution has a LAM model with a precession period $P_ϕ=27.65\\pm0.03~\\text{min}$ and a rotational period $P_ψ=50.49\\pm0.08~\\text{min}$, and the angular momentum points to ecliptic coordinates $(λ, β) = (226^\\mathrm{o}\\pm20^\\mathrm{o}, -39^\\mathrm{o}\\pm20\\mathrm{o})$, although we cannot rule out other solutions or other close-by periods due to aliasing. We also derived a convex shape inversion for the LAM models with consistent rotational parameters but could not find a satisfactory inversion for the SAM models. The corresponding angular momentum points to $(λ, β)=(225^\\mathrm{o}, -43^\\mathrm{o})$, and the periods are $P_ϕ=27.90~\\text{min}$ and $P_ψ=49.66~\\text{min}$. The non-principal-axis rotation provides additional constraints on the dynamic history or the internal structure of Kamo`oalewa.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.00424",
  "author_total": 11,
  "authors": [
    {
      "name": "Xiaoyu Sun"
    },
    {
      "name": "Zhijun Song"
    },
    {
      "name": "Hanjie Tan"
    },
    {
      "name": "Bin Yang"
    },
    {
      "name": "Josef Ďurech"
    },
    {
      "name": "Nicholas Moskovitz"
    },
    {
      "name": "Audrey Thirouin"
    },
    {
      "name": "Samantha Hemmelgarn"
    },
    {
      "name": "Wen Bo"
    },
    {
      "name": "Yang Yu"
    },
    {
      "name": "Jian-Yang Li"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4vbfx3nk614kj.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.00424",
  "fulltext_url": null,
  "id": "4vbfx3nk614kj",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.00424",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ],
    [
      "openalex",
      "3103|Astro and Planetary Science"
    ]
  ],
  "openalex": "W7172399829",
  "pdf_url": "https://arxiv.org/pdf/2608.00424",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4vbfx3nk614kj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:07Z",
      "native_id": "2608.00424",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.00424"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "The Non-Principal-Axis Rotation and Convex Shape Model of Earth Quasi-Satellite and the Target of China's Tianwen-2 Mission (469219) Kamo`oalewa",
  "title_text": "The Non-Principal-Axis Rotation and Convex Shape Model of Earth Quasi-Satellite and the Target of China's Tianwen-2 Mission (469219) Kamo`oalewa",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:07Z",
  "url": "https://research.draconitic.com/paper/4vbfx3nk614kj",
  "venue": "arXiv",
  "versions": []
}