{
  "abstract": "Chemical abundances in the Galactic Centre (GC) are challenging to measure because of high extinction, crowding, and distance, and are typically limited to the brightest AGB and M giants observed in the near-infrared. In contrast, hypervelocity stars (HVSs) ejected from the GC by Sgr A* carry their natal composition into accessible regions such as the Milky Way halo, making them unique probes of GC chemistry. We present high-resolution optical Magellan/MIKE spectroscopy of DESI-312, a bound HVS candidate in the halo with super-solar metallicity ($[\\mathrm{Fe/H}]=0.2\\pm0.1$). This sets it apart from accreted halo populations on radial orbits and is most naturally explained by GC formation and Hills-mechanism ejection. Updated isochrone fits give an age of 7.4-11.3 Gyr; together with its metallicity and kinematics, this strengthens the case for a GC origin. Korg and Turbospectrum spectral synthesis yields $[\\mathrm{X/Fe}]$ for 22 elements, plus Li from an independent line-by-line NLTE analysis. As DESI-312 is near the main sequence, its C, N, and O abundances are unaltered by dredge-up; to our knowledge, these are the first such measurements of unevolved GC material. Its abundance pattern lies where the nuclear star cluster (NSC), nuclear stellar disc (NSD), and inner-bulge sequences overlap, with a Na enhancement ($[\\mathrm{Na/Fe}]=+0.16^{+0.03}_{-0.04}$) more modest than in NSC giants of similar metallicity. Chemistry alone thus cannot identify its progenitor; we nevertheless favour the NSC, given its large reservoir of old, metal-rich stars and the star's kinematics. Alongside WINERED-HVS1 and the S-star S0-6/S10, whose abundances point to different progenitors, this tentatively suggests multiple progenitor populations for the S-star cluster. DESI-312 is a test case for sampling GC chemistry with ejected dwarfs at optical wavelengths, complementing near-infrared studies of giants.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.02409",
  "author_total": 12,
  "authors": [
    {
      "name": "Manuel Cavieres"
    },
    {
      "name": "Darío González Picos"
    },
    {
      "name": "Rogelio Albarracín"
    },
    {
      "name": "Sergey E. Koposov"
    },
    {
      "name": "Elena Maria Rossi"
    },
    {
      "name": "Zephyr Penoyre"
    },
    {
      "name": "Brian Thorsbro"
    },
    {
      "name": "Nils Ryde"
    },
    {
      "name": "Ting S. Li"
    },
    {
      "name": "Christian Aganze"
    },
    {
      "name": "Nasser Mohammed"
    },
    {
      "name": "Mairéad E. Heiger"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1t3h4w9q0b9tp.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.02409",
  "fulltext_url": null,
  "id": "1t3h4w9q0b9tp",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.02409",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.02409",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1t3h4w9q0b9tp.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:20:59Z",
      "native_id": "2611.02409",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.02409"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "Chemical abundances of a Galactic Centre ejecta discovered in DESI",
  "title_text": "Chemical abundances of a Galactic Centre ejecta discovered in DESI",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:18Z",
  "url": "https://research.draconitic.com/paper/1t3h4w9q0b9tp",
  "venue": "arXiv",
  "versions": []
}