{
  "abstract": "We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward interstellar object 3I/ATLAS carried out on UT 2025 December 22 and 23 at a heliocentric distance ( r H ) of 2.37–2.41 au. These measurements of CO, CO 2 , H 2 O, CH 3 OH, and CH 4 sampled molecular chemistry in 3I/ATLAS as it receded from its encounter with our Sun and entered the vicinity of the H 2 O ice line—the region between r H = 2 and 3 au where the temperature becomes too low for H 2 O to vigorously sublime, and CO and CO 2 begin to control the overall activity. CO was the most abundant molecule, followed by H 2 O and CO 2 , whose molecular abundances with respect to CO were (40.5 ± 3.1)% and (41.6 ± 0.3)%, respectively. This work presents spatial–spectral maps of column density and rotational temperature as a function of distance from the nucleus for all detected species. The spatial distributions of both quantities were highly anisotropic for the apolar species in the coma of 3I/ATLAS, yet were more nearly symmetric for the polar molecules. These results demonstrate how volatiles were segregated in the nucleus ices of 3I/ATLAS and reveal heating and cooling mechanisms in its coma. Derived maps of the ortho-to-para ratio (OPR) for H 2 O were flat with increasing distance from the nucleus and consistent with a coma-averaged value OPR = 2.7 ± 0.2, slightly less than the expected equilibrium value of 3.",
  "abstract_shown": true,
  "affiliations": [
    "American University",
    "NASA Goddard Space Flight Center",
    "The Catholic University of America",
    "Sorbonne Université",
    "Auburn University",
    "Physikalisch-Meteorologisches Observatorium Davos und Weltstrahlungszentrum (PMOD/WRC)",
    "Universität Bern",
    "California Institute of Technology",
    "Pioneering Research Institute",
    "University of Maryland",
    "ESA NEO Coordination Centre",
    "University of Edinburgh",
    "Queen’s University Belfast",
    "Northern Arizona University"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 20,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Nathan X. Roth",
      "orcid": "0000-0002-6006-9574"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Martin Cordiner",
      "orcid": "0000-0001-8233-2436"
    },
    {
      "affs": [
        1
      ],
      "name": "Stefanie N. Milam",
      "orcid": "0000-0001-7694-4129"
    },
    {
      "affs": [
        1
      ],
      "name": "Geronimo Luis Villanueva",
      "orcid": "0000-0002-2662-5776"
    },
    {
      "affs": [
        1
      ],
      "name": "Steven B. Charnley",
      "orcid": "0000-0001-6752-5109"
    },
    {
      "affs": [
        3
      ],
      "name": "N. Biver",
      "orcid": "0000-0003-2414-5370"
    },
    {
      "affs": [
        3
      ],
      "name": "Dominique Bockelée-Morvan",
      "orcid": "0000-0002-8130-0974"
    },
    {
      "affs": [
        4
      ],
      "name": "Dennis Bodewits",
      "orcid": "0000-0002-2668-7248"
    },
    {
      "affs": [
        4
      ],
      "name": "Steven Bromley",
      "orcid": "0000-0003-2110-8152"
    },
    {
      "affs": [
        3
      ],
      "name": "J. Crovisier"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "M. N. Drozdovskaya",
      "orcid": "0000-0001-7479-4948"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Sara Faggi",
      "orcid": "0000-0003-0194-5615"
    },
    {
      "affs": [
        7
      ],
      "name": "Davide Farnocchia",
      "orcid": "0000-0003-0774-884X"
    },
    {
      "affs": [
        8
      ],
      "name": "Kenji Furuya",
      "orcid": "0000-0002-2026-8157"
    },
    {
      "affs": [
        9
      ],
      "name": "Michael S. P. Kelley",
      "orcid": "0000-0002-6702-7676"
    },
    {
      "affs": [
        10
      ],
      "name": "M. Micheli",
      "orcid": "0000-0001-7895-8209"
    },
    {
      "affs": [
        4
      ],
      "name": "John W. Noonan",
      "orcid": "0000-0003-2152-6987"
    },
    {
      "affs": [
        11
      ],
      "name": "Cyrielle Opitom",
      "orcid": "0000-0002-9298-7484"
    },
    {
      "affs": [
        12
      ],
      "name": "Megan E. Schwamb",
      "orcid": "0000-0003-4365-1455"
    },
    {
      "affs": [
        13
      ],
      "name": "Cristina A. Thomas",
      "orcid": "0000-0003-3091-5757"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/92q6cmer8jkxm.bib",
  "cited_by": 16,
  "doi": "10.3847/2041-8213/ae7443",
  "fulltext_url": null,
  "id": "92q6cmer8jkxm",
  "issns": [
    "2041-8205",
    "2041-8213"
  ],
  "landing_url": "https://doi.org/10.3847/2041-8213/ae7443",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1912|Astro and Planetary Science"
    ]
  ],
  "openalex": "W7165941055",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-06-24",
  "publisher": "IOP Publishing",
  "ris": "https://research.draconitic.com/paper/92q6cmer8jkxm.ris",
  "sources": [
    {
      "first_seen": "2026-11-07T13:21:01Z",
      "native_id": "W7165941055",
      "source": "openalex",
      "url": "https://doi.org/10.3847/2041-8213/ae7443"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:1912|Astro and Planetary Science",
      "subfield": "planetary"
    }
  ],
  "title": "Coma Physics of an Interstellar Object: JWST Spatial–Spectral Mapping of 3I/ATLAS",
  "title_text": "Coma Physics of an Interstellar Object: JWST Spatial–Spectral Mapping of 3I/ATLAS",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T13:21:19Z",
  "url": "https://research.draconitic.com/paper/92q6cmer8jkxm",
  "venue": "The Astrophysical Journal Letters",
  "versions": []
}