{
  "abstract": "The light curves of nascent eclipsing binaries (EBs) feature sinusoidal reflection effects as a hot B-type main-sequence (MS) primary irradiates the near side of a cool, low-mass, pre-MS companion. We obtained multi-epoch echelle spectra with the MIKE spectrograph on the 6.5m Magellan-Clay Telescope of three nascent EBs embedded in H II regions within the LMC. By fitting atmospheric models to the spectra, the primaries are found to be mid-B dwarfs (T_eff,1 = 18,600-22,800 K; M_1 = 6.8-8.5 Msun). The dynamical masses of the secondaries are only M_2 = 0.38-0.95 Msun, yielding extremely small mass ratios q = M_2/M_1 = 0.05-0.11. Unlike solar-type primaries, which exhibit a dearth of close companions with q < 0.1 known as the brown dwarf desert, massive stars can readily form with very close companions below q < 0.1. By fitting PHOEBE models to the OGLE-III light curves, we measure the secondary radii R_2 = 2.0-2.8 Rsun and temperatures T_eff,2 = 4,000 K. The pre-MS companions are located high on the Hayashi track where evolutionary models indicate ages of only 1 Myr. Their extreme youth suggests that nascent EBs formed via inward disk migration during the previous embedded protostellar phase.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.32931",
  "author_total": 2,
  "authors": [
    {
      "name": "Megan G. Frank"
    },
    {
      "name": "Maxwell Moe"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e4t3dee5crs19.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.32931",
  "fulltext_url": null,
  "id": "e4t3dee5crs19",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.32931",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ],
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7223656010",
  "pdf_url": "https://arxiv.org/pdf/2610.32931",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e4t3dee5crs19.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:15Z",
      "native_id": "2610.32931",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.32931"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "One-Million-Year-Old Nascent Eclipsing Binaries in the LMC",
  "title_text": "One-Million-Year-Old Nascent Eclipsing Binaries in the LMC",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:15Z",
  "url": "https://research.draconitic.com/paper/e4t3dee5crs19",
  "venue": "arXiv",
  "versions": []
}