{
  "id": "2407.17566",
  "version": "v1",
  "published": "2024-07-24T18:00:12.000Z",
  "updated": "2024-07-24T18:00:12.000Z",
  "title": "Stellar Models are Reliable at Low Metallicity: An Asteroseismic Age for the Ancient Very Metal-Poor Star KIC 8144907",
  "authors": [
    "Daniel Huber",
    "Ditte Slumstrup",
    "Marc Hon",
    "Yaguang Li",
    "Victor Aguirre Borsen-Koch",
    "Timothy R. Bedding",
    "Meridith Joyce",
    "J. M. Joel Ong",
    "Aldo Serenelli",
    "Dennis Stello",
    "Travis Berger",
    "Samuel K. Grunblatt",
    "Michael Greklek-McKeon",
    "Teruyuki Hirano",
    "Evan N. Kirby",
    "Marc H. Pinsonneault",
    "Arthur Alencastro Puls",
    "Joel Zinn"
  ],
  "comment": "10 pages, 4 figures, accepted for publication in ApJ",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "Very metal-poor stars ([Fe/H]<-2) are important laboratories for testing stellar models and reconstructing the formation history of our galaxy. Asteroseismology is a powerful tool to probe stellar interiors and measure ages, but few asteroseismic detections are known in very metal-poor stars and none have allowed detailed modeling of oscillation frequencies. We report the discovery of a low-luminosity Kepler red giant (KIC 8144907) with high S/N oscillations, [Fe/H]=-2.66+/-0.08 and [alpha/Fe]=0.38+/-0.06, making it by far the most metal-poor star to date for which detailed asteroseismic modeling is possible. By combining the oscillation spectrum from Kepler with high-resolution spectroscopy we measure an asteroseismic mass and age of 0.79+/-0.02(ran)+/-0.01(sys) Msun and 12.0+/-0.6(ran)+/-0.4(sys) Gyr, with remarkable agreement across different codes and input physics, demonstrating that stellar models and asteroseismology are reliable for very metal-poor stars when individual frequencies are used. The results also provide a direct age anchor for the early formation of the Milky Way, implying that substantial star formation did not commence until redshift z~3 (if the star formed in-situ) or that the Milky Way has undergone merger events for at least ~12 Gyr (if the star was accreted by a dwarf satellite merger such as Gaia Enceladus).",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-07-24T18:00:12.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "stellar models",
      "metal-poor star kic",
      "low metallicity",
      "asteroseismic age",
      "milky way"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}