{
  "abstract": "Context . There have been no robust identifications of fully deuterated methanol, CD ₃ OD, in the interstellar medium (ISM) to date.\n\nAims . Our goal is to continue the search for CD ₃ OD in star-forming regions to determine the deuteration pattern of methanol and set constraints on the deuteration process.\n\nMethods . We used a sensitive imaging spectral survey of the protostellar system IRAS4A in the NGC1333 molecular cloud performed as part of the large program carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) called Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS). The column densities of methanol and several of its less abundant isotopologs, including deuterated ones, were derived under the assumption of local thermodynamic equilibrium (LTE).\n\nResults . Along with the detection of several methanol isotopologs toward the binary component IRAS4A2, we report the first interstellar detection of CD ₃ OD. The deuteration pattern of methanol in IRAS4A2 is similar to the pattern measured in other low-mass protostars, with an increase in the apparent D/H ratio from the singly to multiply deuterated isotopologs. Chemical models of prestellar and protostellar cores focused on deuteration do not reproduce this pattern quantitatively. This discrepancy is even more exacerbated by the detection of CD ₃ OD. Our LTE modeling of the spectra yields low column density ratios of methanol to its ¹³ C and ¹⁸ O isotopologs while the ¹³ C to ¹⁸ O and ¹⁸ O to ¹⁷ O ratios are consistent with the isotopic ratios expected in the local ISM. We suspect that the column density of methanol is underestimated. One possible explanation is that the emission is clumpy rather than monolithic.\n\nConclusions . The first detection of a fully deuterated COM highlights the power of deuterium fractionation as a diagnostic tool for investigating the formation and inheritance of organic molecules during the process of star formation.",
  "abstract_shown": true,
  "affiliations": [
    "Max-Planck-Institut für Radioastronomie",
    "Max-Planck-Institut für extraterrestrische Physik",
    "Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES",
    "Physikalisch-Meteorologisches Observatorium Davos und Weltstrahlungszentrum (PMOD/WRC)",
    "Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP), Universität Bern",
    "Niels Bohr Institute, University of Copenhagen",
    "Department of Physics and Astronomy, Seoul National University",
    "National Radio Astronomy Observatory",
    "Institute of Astronomy, Department of Physics, National Tsinghua University",
    "Univ. Grenoble Alpes, CNRS, IPAG",
    "European Southern Observatory",
    "Star and Planet Formation Laboratory, RIKEN Pioneering Research Institute, Wako-shi"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 15,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "A. Belloche",
      "orcid": "0000-0003-0046-6217"
    },
    {
      "affs": [
        1
      ],
      "name": "S. Spezzano",
      "orcid": "0000-0002-6787-5245"
    },
    {
      "affs": [
        2
      ],
      "name": "A. Coutens",
      "orcid": "0000-0003-1805-3920"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "M. N. Drozdovskaya",
      "orcid": "0000-0001-7479-4948"
    },
    {
      "affs": [
        5
      ],
      "name": "J. K. Jørgensen",
      "orcid": "0000-0001-9133-8047"
    },
    {
      "affs": [
        6
      ],
      "name": "J.-E. Lee",
      "orcid": "0000-0003-3119-2087"
    },
    {
      "affs": [
        7
      ],
      "name": "A. L. Plunkett",
      "orcid": "0000-0002-9912-5705"
    },
    {
      "affs": [
        8
      ],
      "name": "D. Harsono",
      "orcid": "0000-0001-6307-4195"
    },
    {
      "affs": [
        9
      ],
      "name": "S. Maret",
      "orcid": "0000-0003-1104-4554"
    },
    {
      "affs": [
        2
      ],
      "name": "F. Cruz-Sáenz de Miera",
      "orcid": "0000-0002-4283-2185"
    },
    {
      "affs": [
        6
      ],
      "name": "J.-H. Jeong",
      "orcid": "0009-0005-6319-8485"
    },
    {
      "affs": [
        10
      ],
      "name": "P. Nazari",
      "orcid": "0000-0002-4448-3871"
    },
    {
      "affs": [
        11
      ],
      "name": "Y.-L. Yang",
      "orcid": "0000-0001-8227-2816"
    },
    {
      "affs": [
        6
      ],
      "name": "H.-S. Yun",
      "orcid": "0000-0001-6842-1555"
    },
    {
      "affs": [
        11
      ],
      "name": "S. Zeng",
      "orcid": "0000-0003-3721-374X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aq7swdk6rdypg.bib",
  "cited_by": 0,
  "doi": "10.1051/0004-6361/202659642",
  "fulltext_url": null,
  "id": "aq7swdk6rdypg",
  "issns": [
    "0004-6361",
    "1432-0746"
  ],
  "landing_url": "https://www.aanda.org/10.1051/0004-6361/202659642",
  "language": null,
  "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": [
    [
      "openalex",
      "3103|Astrophysics and Star Formation Studies"
    ]
  ],
  "openalex": "W7220843300",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-07",
  "publisher": "EDP Sciences",
  "ris": "https://research.draconitic.com/paper/aq7swdk6rdypg.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:18Z",
      "native_id": "10.1051/0004-6361/202659642",
      "source": "crossref",
      "url": "https://www.aanda.org/10.1051/0004-6361/202659642"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Astrophysics and Star Formation Studies",
      "subfield": "stellar"
    }
  ],
  "title": "Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS)",
  "title_text": "Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS)",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:18Z",
  "url": "https://research.draconitic.com/paper/aq7swdk6rdypg",
  "venue": "Astronomy & Astrophysics",
  "versions": []
}