{
  "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 2078 such stars from more than two million Gaia Data Release 3 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 ∼11.5 Gyr and [Fe/H] ≃ − 0.59, and an older and more metal-poor component with a peak age of ∼12.5 Gyr and [Fe/H] ≃ − 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 ∼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": [
    "Chinese Academy of Sciences",
    "Beijing Normal University",
    "University of Chinese Academy of Science"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Tiancheng Sun",
      "orcid": "0000-0003-0795-4854"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Maosheng Xiang",
      "orcid": "0000-0002-5818-8769"
    },
    {
      "affs": [
        1
      ],
      "name": "Shaolan Bi",
      "orcid": "0000-0002-7642-7583"
    },
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Jifeng Liu",
      "orcid": "0000-0002-2874-2706"
    },
    {
      "affs": [
        0
      ],
      "name": "Meng Zhang",
      "orcid": "0000-0001-9293-131X"
    },
    {
      "affs": [
        0
      ],
      "name": "Yaqian Wu",
      "orcid": "0000-0002-8337-4117"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9magbv0tp13v1.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-3881/aeac24",
  "fulltext_url": null,
  "id": "9magbv0tp13v1",
  "issns": [
    "0004-6256",
    "1538-3881"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-3881/aeac24",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7222504745",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-3881/aeac24/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/9magbv0tp13v1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:14Z",
      "native_id": "10.3847/1538-3881/aeac24",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-3881/aeac24"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "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": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:14Z",
  "url": "https://research.draconitic.com/paper/9magbv0tp13v1",
  "venue": "The Astronomical Journal",
  "versions": [
    {
      "doi": "10.48550/arxiv.2610.26374",
      "pid": "fghxs1rgwcwe1",
      "relation": "preprint",
      "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": "arXiv"
    }
  ]
}