{
  "abstract": "Recent JWST observations have revealed a sample of high-$z$ galaxies with highly enhanced N/O abundance ratios, $\\log\\rm (N/O)\\gtrsim -1.1$. Strong optically-thick winds of rotating massive stars going through the Wolf-Rayet (WR) phase provide a viable explanation for such N/O enhancements, supported by the direct spectroscopic WR signatures discovered in a few galaxies. Such strong winds are also needed to reproduce the single WR stars in the Small Magellanic Cloud (SMC). Here, we compute the metal yields of massive ($\\sim 20-100\\ \\rm M_\\odot$), metal-poor stars using two sets of MESA single stellar evolution models with and without optically-thick winds in a dense grid of metallicities ($Z_\\star\\sim 0.001-0.0045$) and initial spins ($ω\\equivΩ/Ω_{\\rm crit}\\sim 0-0.7$). Considering an initial spin distribution based on observations of O-type stars in the SMC, we find that both sets produce strong N/O enhancements up to $\\rm \\log(N/O)\\sim 0.1$ within a few Myr after a starburst. The models with optically-thick winds undergo a rapid transition from high N/O to the `normal' state of $\\rm \\log(N/O)\\sim -1.5$ at $t\\sim 3-4$ Myr driven by C/O-rich winds, while the transition is slower and weaker without optically-thick winds. The optically-thick-wind scenario can reproduce the nebular C, N, O, and He abundance patterns of three representative high-$z$ galaxies showing direct WR signatures: RXCJ2248-ID, Sunburst Arc, and MARTA 4327, with stellar metallicities and ages similar to those inferred from SED-fitting. This can be interpreted as a coherent evolution sequence captured before ($t\\lesssim 3$ Myr), during ($t\\sim 3-4$ Myr), and after ($t\\gtrsim 5$ Myr) the transition. In contrast, the optically-thin-wind-only scenario ejects much less C and O via winds and cannot reproduce Sunburst Arc and MARTA 4327. The yields are available at https://zenodo.org/records/22897057.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.26998",
  "author_total": 4,
  "authors": [
    {
      "name": "Boyuan Liu"
    },
    {
      "name": "Michela Mapelli"
    },
    {
      "name": "Lumen Boco"
    },
    {
      "name": "Xihan Ji"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/csc20zdrkabgd.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.26998",
  "fulltext_url": null,
  "id": "csc20zdrkabgd",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.26998",
  "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",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7214161158",
  "pdf_url": "https://arxiv.org/pdf/2609.26998",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/csc20zdrkabgd.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:54Z",
      "native_id": "2609.26998",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.26998"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "N/O-enhanced chemical enrichment by massive stars: the interplay of optically-thick winds and rotation",
  "title_text": "N/O-enhanced chemical enrichment by massive stars: the interplay of optically-thick winds and rotation",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:54Z",
  "url": "https://research.draconitic.com/paper/csc20zdrkabgd",
  "venue": "arXiv",
  "versions": []
}