{
  "abstract": "CH3OH masers that are collisionally pumped, referred to as `class I', commonly trace shock interfaces in star-forming regions, but their incidence in low-mass protostars remains poorly quantified. We use data from the COMPASS ALMA Large Program to establish the occurrence, spatial origin, and excitation of a newly detected class I CH3OH maser at 302.9 GHz towards low-mass protostars and to test whether its pumping environments exhibit signatures of shock-driven complex chemistry. COMPASS provides unbiased line surveys of 11 sources between 279.0 and 311.7 GHz at typical angular resolutions of 0.3\"-0.5\". Rotation diagram analysis of departures from LTE in the 302.9 GHz CH3OH excitation robustly reveals masing in seven of 11 sources, with peak brightness temperatures from a few to ~10^3 K. The brightest detection is towards HOPS 108 and is likely associated with the powerful outflow from the nearby intermediate-mass protostar HOPS 370. Excluding this case, the maser is detected in six of ten low-mass protostars (60%). All six are Class 0 sources interacting with dense ambient material, whereas the non-detections comprise three Class I sources and one isolated Class 0 core, indicating a preference for early evolutionary stages and gas-rich environments for outflow-ambient medium interactions. The maser emission is spatially coincident with thermal CH3OH along outflow cavity walls and bow shocks, but is more compact and knot-like. Among the surveyed COMs, only CH3CHO closely traces the shocked morphology of the 302.9 GHz maser, and only around HOPS 108. These results show that class I CH3OH masers in low-mass protostellar systems are more prevalent than previously recognised and preferentially occur in younger, more embedded sources. More sensitive CH3CHO observations are needed to test whether a similar relationship with shock-driven chemistry also applies in the low-mass regime.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.08158",
  "author_total": 19,
  "authors": [
    {
      "name": "Jae-Hong Jeong"
    },
    {
      "name": "Jeong-Eun Lee"
    },
    {
      "name": "Jes K. Jørgensen"
    },
    {
      "name": "Audrey Coutens"
    },
    {
      "name": "Maria N. Drozdovskaya"
    },
    {
      "name": "Adele L. Plunkett"
    },
    {
      "name": "Arnaud Belloche"
    },
    {
      "name": "Sébastien Maret"
    },
    {
      "name": "Hyeong-Sik Yun"
    },
    {
      "name": "Fernando Cruz-Sáenz de Miera"
    },
    {
      "name": "Daniel Harsono"
    },
    {
      "name": "Merel L. R. van 't Hoff"
    },
    {
      "name": "Chul-Hwan Kim"
    },
    {
      "name": "Ágnes Kóspál"
    },
    {
      "name": "Brett A. McGuire"
    },
    {
      "name": "Pooneh Nazari"
    },
    {
      "name": "Silvia Spezzano"
    },
    {
      "name": "Yao-Lun Yang"
    },
    {
      "name": "Shaoshan Zeng"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/257vgvsmmjndh.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.08158",
  "fulltext_url": null,
  "id": "257vgvsmmjndh",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.08158",
  "language": null,
  "licence": "CC-BY-NC-SA-4.0",
  "licence_label": "CC BY-NC-SA 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-sa/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "openalex",
      "3103|Astrophysics and Star Formation Studies"
    ]
  ],
  "openalex": "W7221049150",
  "pdf_url": "https://arxiv.org/pdf/2610.08158",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/257vgvsmmjndh.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:22Z",
      "native_id": "2610.08158",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.08158"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) VI. Discovery of a class I methanol maser transition and its association with acetaldehyde",
  "title_text": "Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) VI. Discovery of a class I methanol maser transition and its association with acetaldehyde",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:22Z",
  "url": "https://research.draconitic.com/paper/257vgvsmmjndh",
  "venue": "arXiv",
  "versions": []
}