{
  "abstract": "Stars born in the high-$α$ disk can later acquire low angular momentum through dynamical scattering during early merger events. Their age--metallicity distribution thus provides a fossil record of the history of both star formation and dynamical perturbations in the early Milky Way disk. Here we identify a sample of 2,078 such stars from more than two million Gaia DR3 subgiants with robust determinations of ages, kinematics, and abundances. From this sample we reconstruct their intrinsic age--metallicity distribution with a forward modeling approach. Our results confirm that these scattered stars are older and more metal-poor than the bulk of the high-$α$ disk on average. In particular, the joint age--metallicity distribution reveals a robust two-component feature: a broad, dominant component with a peak age of $\\sim$11.5~Gyr and ${\\rm [Fe/H]}\\simeq-0.59$, and an older and more metal-poor component with a peak age of $\\sim$12.5~Gyr and ${\\rm [Fe/H]}\\simeq-0.86$. The presence of this two-component structure suggests that the high-$α$ disk experienced episodic phases of star formation and chemical enrichment. The age distribution of the younger Splash component, compared with that of the high-$α$ disk, provides evidence for a substantial dynamical perturbation at a lookback time of 10.8--11.5~Gyr, possibly associated with an early passage of Gaia--Sausage--Enceladus (GSE). The older Splash component, with a peak age of $\\sim$12.5~Gyr, may preserve signatures of an earlier interaction, possibly associated with the proposed Low-energy--Kraken--Heracles (LKH) event.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: AJ, 172, 271 (2026)",
  "arxiv": "2610.26374",
  "author_total": 6,
  "authors": [
    {
      "name": "Tiancheng Sun"
    },
    {
      "name": "Maosheng Xiang"
    },
    {
      "name": "Shaolan Bi"
    },
    {
      "name": "Jifeng Liu"
    },
    {
      "name": "Meng Zhang"
    },
    {
      "name": "Yaqian Wu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fghxs1rgwcwe1.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.26374",
  "fulltext_url": null,
  "id": "fghxs1rgwcwe1",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.26374",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.26374",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fghxs1rgwcwe1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2610.26374",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.26374"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "The Milky Way's Early Disk Was Built in Bursts. I. Evidence from Low-angular-momentum, High-$α$ Stars Scattered Out of the Protodisk by Merger Events",
  "title_text": "The Milky Way's Early Disk Was Built in Bursts. I. Evidence from Low-angular-momentum, High-α Stars Scattered Out of the Protodisk by Merger Events",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/fghxs1rgwcwe1",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-3881/aeac24",
      "pid": "9magbv0tp13v1",
      "relation": "published-as",
      "title": "The Milky Way’s Early Disk Was Built in Bursts. I. Evidence from Low-angular-momentum, High- α Stars Scattered Out of the Protodisk by Merger Events",
      "venue": "The Astronomical Journal"
    }
  ]
}