{
  "abstract": "We analyze the post-perihelion coma of the Great Comet of 2024, C/2023 A3 (Tsuchinshan--ATLAS) to characterize dust activity and assess the contribution of sublimating icy grains to a candidate near-nucleus halo. Using archival Zwicky Transient Facility images from 15 February to 26 May 2025, we performed aperture photometry within a fixed projected radius of 40,000 km and derived azimuthally averaged surface-brightness profiles. The comet faded from 12.86 to 14.77 mag as heliocentric distance increased from 2.64 to 3.90 au, with two short-lived brightenings. The effective dust cross section decreased by a factor of 2.4, following $C_{\\rm e}\\propto r_{\\rm h}^{-3.1}$, while the dust mass production rate scaled as $\\dot{M}_{\\rm d}\\propto r_{\\rm h}^{-3.41}$, consistent with a contribution from water-ice-driven activity. Extrapolating the fitted relation to perihelion implies a model-dependent cumulative dust mass loss of $3.0\\times10^{11}$ kg, equivalent to a globally averaged erosion depth of $\\sim1.4$ m for an assumed nucleus radius of 5.9 km. Coma profiles were shallower than the canonical steady-state expectation, suggesting radial changes in dust distribution or scattering properties, possibly due to delayed aggregate fragmentation. A persistent central brightness excess, coincident with less-red inner-coma colors, is consistent with an icy-grain halo. Among the models explored, icy grains of radius $\\sim10~μ$m with carbon fraction $\\sim0.1\\%$ yield halo radii comparable to those observed during enhanced activity on 21--25 February 2025, with grain lifetimes of $2.8\\times10^5$--$3.2\\times10^5$ s. No single fixed grain size and composition reproduces the full halo evolution; an increasing carbon fraction could explain the broad halo-radius trend, possibly reflecting progressive refractory enrichment of near-surface material.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: A&A, 714, A143 (2026)",
  "arxiv": "2610.21228",
  "author_total": 4,
  "authors": [
    {
      "name": "Bin Liu"
    },
    {
      "name": "Xiaoping Zhang"
    },
    {
      "name": "Xiaodong Liu"
    },
    {
      "name": "Man-To Hui"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2v382s8ptdx7y.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.21228",
  "fulltext_url": null,
  "id": "2v382s8ptdx7y",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.21228",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.21228",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2v382s8ptdx7y.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2610.21228",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.21228"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "Post-perihelion dust activity and a candidate icy-grain halo in long-period comet C/2023 A3 (Tsuchinshan--ATLAS)",
  "title_text": "Post-perihelion dust activity and a candidate icy-grain halo in long-period comet C/2023 A3 (Tsuchinshan--ATLAS)",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/2v382s8ptdx7y",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1051/0004-6361/202661392",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}