{
  "abstract": "The majority of very close binaries (orbital periods P < 5 days) are in triples. Previous studies surmised that the tertiary hardened the inner binary via Kozai–Lidov cycles coupled with tidal friction. Alternatively, the trend could be due to a common origin, e.g., more massive molecular cores and protostellar disks are more likely to fragment twice into a triple and harden the inner binary to very short periods via disk migration. Disk migration occurs during the embedded Class I protostellar phase while secular evolution with a tertiary occurs on much longer timescales. To determine the dominant migration mechanism, I accurately measure the very close binary fractions of both late-type and early-type primaries in star-forming environments. After combining five surveys, the late-type Class II/III T Tauri very close binary fraction is F VCB = 2.1 − 0.5 + 1.0 %, which is consistent with the measurement for late-type field main-sequence (MS) stars (1.7% ± 0.1%). More than 85% of very close late-type binaries hardened via disk migration during the Class I protostellar phase. I next measure the OGLE-III eclipsing binary (EB) fractions of young massive stars in the LMC. The very close EB fractions of massive young stellar objects (YSOs; F VCEB = 8.3 − 3.2 + 4.9 %), OB stars near massive YSOs (4.7% ± 0.8%), and OB stars in small, young H II regions (6.4% ± 1.5%) are consistent with each other and the measurement for OB stars in slightly older clusters (4.7% ± 0.3%). More than 90% of very close massive binaries hardened via disk migration during the embedded protostellar phase.",
  "abstract_shown": true,
  "affiliations": [
    "University of Wyoming"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Maxwell Moe",
      "orcid": "0000-0002-0870-6388"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2h0wdhsjrckyr.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4357/aea147",
  "fulltext_url": null,
  "id": "2h0wdhsjrckyr",
  "issns": [
    "0004-637X",
    "1538-4357"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea147",
  "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": "W7206178107",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea147/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/2h0wdhsjrckyr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:11Z",
      "native_id": "10.3847/1538-4357/aea147",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea147"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Astrophysics and Star Formation Studies",
      "subfield": "stellar"
    }
  ],
  "title": "The Formation of Very Close Binary Stars",
  "title_text": "The Formation of Very Close Binary Stars",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:11Z",
  "url": "https://research.draconitic.com/paper/2h0wdhsjrckyr",
  "venue": "The Astrophysical Journal",
  "versions": []
}