{
  "abstract": "We compare the physical properties of inner-Earth asteroid (163693) Atira with the NEOMOD3 population model. Its radar-derived diameter of 4.9 km and absolute magnitude H$_V\\simeq$16.4 imply a geometric albedo of p$_V\\sim$0.02. Photometry with the Astrophysical Research Consortium 3.5-m telescope and ARCTIC yields g-r=0.49$\\pm$0.03, r-i=0.20$\\pm$0.02, i-z=0.02$\\pm$0.03, a$^\\ast$=$-0.05\\pm0.03$, and a g-to-i spectral slope of 3.4$\\pm$0.9$\\%$/100 nm. The photometric reflectance favors a provisional X-type classification; combined with the low albedo, it supports a Tholen P-type interpretation. NEOMOD3 assigns an approximately 66$\\%$ probability of delivery through inner Main Belt channels and 26$\\%$ to central and outer Main Belt channels. Atira's NEOMOD3 albedo-category probabilities are $0.07\\pm0.02$, $0.64\\pm0.04$, and $0.29\\pm0.04$ for p$_V<$0.1, 0.1$\\leq$p$_V<$0.3, and p$_V\\geq$0.3, respectively. Across 38 inner-Earth objects, including Atira and 'Ayló'chaxnim, inner Main Belt delivery generally dominates, and intermediate albedo is favored for 33 objects. Atira therefore represents an uncommon low-albedo outcome, compatible with delivery of dark material from the inner Main Belt or more distant primitive populations. Further characterization of inner-Earth asteroids will test whether current population models reproduce their compositional diversity.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.40114",
  "author_total": 11,
  "authors": [
    {
      "name": "Bryce T. Bolin"
    },
    {
      "name": "Carl Ingebretsen"
    },
    {
      "name": "Robert Jedicke"
    },
    {
      "name": "William F. Bottke"
    },
    {
      "name": "Colin Orion Chandler"
    },
    {
      "name": "Rogerio Deienno"
    },
    {
      "name": "Alessandro Morbidelli"
    },
    {
      "name": "David Nesvorný"
    },
    {
      "name": "Leo Y. Alcorn"
    },
    {
      "name": "Percy Gomez"
    },
    {
      "name": "Meredith A. MacGregor"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8vv6f1mb7wepm.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.40114",
  "fulltext_url": null,
  "id": "8vv6f1mb7wepm",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.40114",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.40114",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-29",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8vv6f1mb7wepm.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:28Z",
      "native_id": "2610.40114",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.40114"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "The dark surface of (163693) Atira and implications for inner-Earth asteroid origins",
  "title_text": "The dark surface of (163693) Atira and implications for inner-Earth asteroid origins",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:47Z",
  "url": "https://research.draconitic.com/paper/8vv6f1mb7wepm",
  "venue": "arXiv",
  "versions": []
}