{
  "abstract": "Massive prestellar cores are a central assumption of core-accretion models of high-mass star formation, yet convincing observational examples remain rare. The \"dragon egg\" (C2c1a) core in the infrared-dark cloud G028.37+00.07 has been proposed as a promising compact high-mass core candidate. We present new ALMA Band 6 observations at $0.035''$-$0.078''$ ($\\sim175$-400 au at 5 kpc), providing one of the most stringent high-resolution tests of such a candidate. The region resolves into multiple fragments, but the brightest component, C2c1a(a), remains a single compact continuum peak down to $\\sim175$ au, with a deconvolved radius of $\\sim87$ au and a nearest neighbouring fragment at a projected separation of $\\sim2400$ au. The continuum peak reaches a brightness temperature of $\\sim40$ K, exceeding the $\\sim10$ K gas temperatures inferred from lower-resolution NH$_3$ observations and indicating a strong radial temperature gradient. Continuum-based mass estimates range from $\\sim2$ to $\\sim30$ $M_\\odot$ (implying extreme densities of $n_\\mathrm{H2} > 10^9$cm$^{-3}$), depending on temperature, while lower-resolution data indicate a much larger mass reservoir of $\\sim110$ $M_\\odot$ on $\\sim10^4$ au scales. The spectrum shows no strong hot-core tracers and only weak, spatially extended H$_2$CO and CO emission; no high-velocity outflow can be unambiguously associated with C2c1a(a). We conclude that C2c1a(a) is an exceptionally compact core embedded within a massive cold reservoir, with no additional compact fragments detected within the present resolution and sensitivity limits, potentially tracing the earliest formation of a central protostellar \"seed\" within a still-dominant reservoir. [abridged]",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.07138",
  "author_total": 17,
  "authors": [
    {
      "name": "A. T. Barnes"
    },
    {
      "name": "J. D. Henshaw"
    },
    {
      "name": "Á. Sánchez-Monge"
    },
    {
      "name": "P. Caselli"
    },
    {
      "name": "I. Jiménez-Serra"
    },
    {
      "name": "J. E. Pineda"
    },
    {
      "name": "K. Immer"
    },
    {
      "name": "M. De Simone"
    },
    {
      "name": "R. J. Parker"
    },
    {
      "name": "F. Fontani"
    },
    {
      "name": "E. Redaelli"
    },
    {
      "name": "S. N. Longmore"
    },
    {
      "name": "L. Böhm"
    },
    {
      "name": "Q. Zhang"
    },
    {
      "name": "C. Y. Law"
    },
    {
      "name": "G. Cosentino"
    },
    {
      "name": "J. C. Tan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/575q311jmpaxn.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.07138",
  "fulltext_url": null,
  "id": "575q311jmpaxn",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.07138",
  "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.GA"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.07138",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/575q311jmpaxn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:22Z",
      "native_id": "2610.07138",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.07138"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "Cracking open the \"dragon egg\": ALMA 1.3mm observations of a compact, young high-mass core candidate at 30mas resolution",
  "title_text": "Cracking open the \"dragon egg\": ALMA 1.3mm observations of a compact, young high-mass core candidate at 30mas resolution",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:22Z",
  "url": "https://research.draconitic.com/paper/575q311jmpaxn",
  "venue": "arXiv",
  "versions": []
}