{
  "abstract": "Constraining ionization and excitation processes in protoplanetary disks is essential for understanding the chemical structure and evolution of disk material, shaping planet formation pathways. We present JWST/NIRSpec integral-field-unit observations of the edge-on disk Oph 163131, which reveal an unusual rovibrational H 2 spectrum dominated by the 1–0 O(2) line (2.627 μ m), with suppressed higher- J emission despite excitation to v = 2 and 3. This vibrationally hot, rotationally cold H 2 emission is spatially extended, broadly following the molecular disk traced by CO( J = 2–1), with emission increasing above and below a thin midplane dark lane and extending radially beyond ∼200 au, where near-IR scattered-light emission is no longer dominant. We interpret the observed H 2 emission as arising from nonthermal excitation in cold, dense outer-disk gas, where collisions depopulate higher- J rotational levels within each vibrational manifold prior to emission, producing the characteristic “ v -hot, J -cold” spectrum. We consider both ultraviolet irradiation and cosmic-ray excitation as contributors to the H 2 emission and find that their combined action, together with collisional deexcitation of high- J level populations, broadly reproduces the observed line ratios and morphology. Within this framework, we infer a rather high effective cosmic-ray ionization rate of ∼(1–10) × 10 −15 s −1 in the presence of a moderate UV field ( χ UV = 100−1000, in Draine units). These results for disks, together with the recent findings by Bialy et al. for the lower-density starless core B68, highlight the potential of ro-vibrational H 2 emission as a novel probe of cosmic-ray ionization.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.09407",
  "author_total": 22,
  "authors": [
    {
      "name": "Korash Assani"
    },
    {
      "name": "Zhi-Yun Li"
    },
    {
      "name": "Jennifer Bergner"
    },
    {
      "name": "David Neufeld"
    },
    {
      "name": "Daniel Harsono"
    },
    {
      "name": "Maria Drozdovskaya"
    },
    {
      "name": "Marco Padovani"
    },
    {
      "name": "Emmanuel Dartois"
    },
    {
      "name": "Jennifer A. Noble"
    },
    {
      "name": "Nicole Arulanantham"
    },
    {
      "name": "Alice Booth"
    },
    {
      "name": "Yao-Lun Yang"
    },
    {
      "name": "Mayank Narang"
    },
    {
      "name": "Will Thompson"
    },
    {
      "name": "Elizabeth Yunerman"
    },
    {
      "name": "Karin Öberg"
    },
    {
      "name": "Julia Santos"
    },
    {
      "name": "Charles Mentzer"
    },
    {
      "name": "Jon Ramsey"
    },
    {
      "name": "Lukas Welzel"
    },
    {
      "name": "Klaus Pontoppidan"
    },
    {
      "name": "Melissa Mcclure"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0r1tm4qvm286x.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-3881/ae947a",
  "fulltext_url": null,
  "id": "0r1tm4qvm286x",
  "issns": [
    "0004-6256",
    "1538-3881"
  ],
  "landing_url": "https://hal.science/hal-05850293v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.phys"
    ],
    [
      "hal",
      "1.phys.astr"
    ],
    [
      "openalex",
      "3103|Astrophysics and Star Formation Studies"
    ]
  ],
  "openalex": "W7204106320",
  "pdf_url": "https://hal.science/hal-05850293/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-24",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/0r1tm4qvm286x.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T12:20:52Z",
      "native_id": "hal-05850293",
      "source": "hal",
      "url": "https://hal.science/hal-05850293v1"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Astrophysics and Star Formation Studies",
      "subfield": "stellar"
    }
  ],
  "title": "JWST Edge-on Disk Ice (JEDIce): Vibrationally Hot, Rotationally Cold H 2 in the Outer Disk of Oph 163131 Nonthermally Excited by Ultraviolet and Cosmic Rays",
  "title_text": "JWST Edge-on Disk Ice (JEDIce): Vibrationally Hot, Rotationally Cold H 2 in the Outer Disk of Oph 163131 Nonthermally Excited by Ultraviolet and Cosmic Rays",
  "type": "peer-reviewed",
  "updated_at": "2026-11-05T12:20:12Z",
  "url": "https://research.draconitic.com/paper/0r1tm4qvm286x",
  "venue": "The Astronomical Journal",
  "versions": []
}