{
  "abstract": "From their discovery as radio pulsars to landmark multi-messenger observations of their mergers, double neutron stars have transformed our understanding of the extreme Universe and the formation of heavy elements (Drout et al. 2017; Abbott et al. 2017). Yet, uncertainties in their formation result in predicted merger rates spanning orders of magnitude (Tauris et al. 2017; Mandel & Broekgaarden 2022). The most critical stage occurs when a star is stripped of its hydrogen-rich envelope, causing the binary orbit to shrink drastically. Despite its fundamental role, the resulting tight binaries comprising a stripped star and neutron star have remained elusive. Here we report a $\\sim$$3.4\\,M_{\\odot}$ stripped star (Ludwig et al. 2026; Drout et al. 2023; Götberg et al. 2023) orbiting an unseen companion every 4.2 hours. Our orbital and spectroscopic analysis excludes a normal star, which would not fit within the orbit, as well as a second stripped star which would have been detectable in our spectra. Adding constraints from high cadence photometry gives a 99.4% probability that the companion is too massive to be a white dwarf, making a neutron star the most likely companion. We model the system's future and predict that the stripped star will transfer mass again before exploding as a hydrogen-free supernova, leaving a bound pair of neutron stars that will merge after 220 Myr. This system reveals a previously unconstrained phase of binary evolution, uncovering a new class of systems that probes the uncertain physics of massive stars, linking to observable gravitational-wave sources.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.35539",
  "author_total": 11,
  "authors": [
    {
      "name": "Bethany Ludwig"
    },
    {
      "name": "Maria R. Drout"
    },
    {
      "name": "Ylva Götberg"
    },
    {
      "name": "Alexander Laroche"
    },
    {
      "name": "Katie Auchettl"
    },
    {
      "name": "Alejandro Vigna-Gómez"
    },
    {
      "name": "Katelyn Breivik"
    },
    {
      "name": "Cole Johnston"
    },
    {
      "name": "Eva Laplace"
    },
    {
      "name": "Vikram S. Dhillon"
    },
    {
      "name": "Hugues Sana"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/28pjc5k0kmwff.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.35539",
  "fulltext_url": null,
  "id": "28pjc5k0kmwff",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.35539",
  "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.HE"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ],
    [
      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
    ]
  ],
  "openalex": "W7223898830",
  "pdf_url": "https://arxiv.org/pdf/2610.35539",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/28pjc5k0kmwff.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.35539",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.35539"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "An Intermediate Mass Stripped Star in a 4.2-hour Orbit around a Compact Object",
  "title_text": "An Intermediate Mass Stripped Star in a 4.2-hour Orbit around a Compact Object",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/28pjc5k0kmwff",
  "venue": "arXiv",
  "versions": []
}