{
  "abstract": "A central goal of gravitational-wave astronomy is to use merging binary black hole (BBH), black hole-neutron star (BHNS), and binary neutron star (BNS) systems as fossils to reconstruct the formation and evolution of massive stars across cosmic time. In practice, this inference relies on population-synthesis models that map massive stellar binaries to merging compact objects. However, these models disagree on the dominant orbital-hardening mechanisms within isolated binary evolution, particularly on whether common-envelope (CE) evolution is required. To address this, we compile and systematically compare formation-channel predictions from more than 200 isolated-binary population-synthesis simulations, organized within a unified hierarchical taxonomy. We find that BBH and BHNS formation pathways span nearly the full allowed range from CE-dominated to without-CE-dominated evolution (0-100%), while often predicting similar merger rates, revealing a fundamental degeneracy: merger-rate measurements alone do not uniquely constrain the underlying evolutionary pathways. In contrast, BNS formation proceeds almost exclusively through channels involving at least one CE phase (>90-100%), suggesting CE evolution plays a qualitatively different role in BNS than in BBH and BHNS formation. The relative contributions of with-CE and without-CE pathways are governed primarily by assumptions controlling mass-transfer stability, angular-momentum loss, CE efficiency, and supernova physics, which often act non-linearly and in correlated fashion, such that trends from one-at-a-time parameter variations do not generalize across simulation frameworks. Robust interpretation of gravitational-wave populations will therefore require transparent formation-channel definitions, reproducible analysis pipelines, systematic cross-code comparisons, and observational constraints that extend beyond merger rates alone.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.05322",
  "author_total": 17,
  "authors": [
    {
      "name": "Floor S. Broekgaarden"
    },
    {
      "name": "Ana Lam"
    },
    {
      "name": "Sasha Levina"
    },
    {
      "name": "Jakub Klencki"
    },
    {
      "name": "Kyle A. Rocha"
    },
    {
      "name": "Lieke van Son"
    },
    {
      "name": "Steffani M. Grondin"
    },
    {
      "name": "Monica Gallegos-Garcia"
    },
    {
      "name": "Brian D. Metzger"
    },
    {
      "name": "Enrico Ramirez-Ruiz"
    },
    {
      "name": "Angela Twum"
    },
    {
      "name": "Melanie Santiago"
    },
    {
      "name": "Julia Haynes"
    },
    {
      "name": "Tyler B. Smith"
    },
    {
      "name": "Amedeo Romagnolo"
    },
    {
      "name": "Edo Berger"
    },
    {
      "name": "Lucas M. de Sá"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5bzxen0zbyvbq.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.05322",
  "fulltext_url": null,
  "id": "5bzxen0zbyvbq",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.05322",
  "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.HE"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.05322",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5bzxen0zbyvbq.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:50Z",
      "native_id": "2606.05322",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.05322"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "How Common Are Common Envelopes? Quantifying Their Role in Forming Gravitational-Wave Sources",
  "title_text": "How Common Are Common Envelopes? Quantifying Their Role in Forming Gravitational-Wave Sources",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:50Z",
  "url": "https://research.draconitic.com/paper/5bzxen0zbyvbq",
  "venue": "arXiv",
  "versions": []
}