{
  "id": "2110.06432",
  "version": "v1",
  "published": "2021-10-13T01:29:27.000Z",
  "updated": "2021-10-13T01:29:27.000Z",
  "title": "A Nuclear Equation of State Inferred from Stellar r-Process Abundances",
  "authors": [
    "Erika M. Holmbeck",
    "Richard O'Shaughnessy",
    "Vera Delfavero",
    "Krzysztof Belczynski"
  ],
  "comment": "14 pages, 7 figures",
  "categories": [
    "astro-ph.HE",
    "nucl-th"
  ],
  "abstract": "Binary neutron star mergers (NSMs) have been confirmed as one source of the heaviest observable elements made by the rapid neutron-capture (r-) process. However, modeling NSM outflows -- from the total ejecta masses to their elemental yields -- depends on the unknown nuclear equation of state (EOS) that governs neutron-star structure. In this work, we derive a phenomenological EOS by assuming that NSMs are the dominant sources of the heavy-element material in metal-poor stars with r-process abundance patterns. We start with a population synthesis model to obtain a population of merging neutron star binaries and calculate their EOS-dependent elemental yields. Under the assumption that these mergers were responsible for the majority of r-process elements in the metal-poor stars, we find parameters representing the EOS for which the theoretical NSM yields reproduce the derived abundances from observations of metal-poor stars. For our proof-of-concept assumptions, we find an EOS that is slightly softer than, but still in agreement with, current constraints, e.g., by the Neutron Star Interior Composition Explorer (NICER), with $R_{1.4}=12.25\\pm 0.03$~km and $M_{\\textrm TOV}$ of $2.17\\pm 0.03$~M$_\\odot$(statistical uncertainties, neglecting modeling systematics).",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-10-13T01:29:27.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "stellar r-process abundances",
      "nuclear equation",
      "metal-poor stars",
      "neutron star interior composition explorer",
      "elemental yields"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}