{
  "abstract": "We present a new approach to constraining the delay time distribution (DTD) governing r - and s -process element production. Rather than using metallicity as a proxy for time, we work directly with stellar ages at solar metallicity, where chemical equilibrium models are most applicable. We analyze two complementary samples: more than 10,000 red clump (RC) thin disk stars at solar metallicity from LAMOST, and solar twins with high-precision abundances; both have well-determined stellar ages τ . We fit chemical equilibrium models with power-law DTDs to the evolution of [Eu/Mg]( τ ) and [Ba/Mg]( τ ) in each sample, taking europium as a canonical r -process element and barium as an s -process element, each referenced to magnesium as a near-instantaneous, CCSN-dominated element. To validate the method, we first apply it to [Fe/Mg]( τ ) and recover that ≈70% of Fe comes from a delayed channel with a declining DTD ∝ t −1.2 , in agreement with well-established results for iron production in thermonuclear supernovae. It also shows that about 60% of Eu and Ba forming today originate from strongly delayed processes, and the inferred delayed-production rates of both Eu and Ba rise with delay time, opposite to that of thermonuclear supernovae. These results provide direct temporal constraints on r - and s -process enrichment, complementary to metallicity-based chemical evolution studies. Because we model the abundance referenced to Mg, and the same trend is recovered across stars of different guiding-center radii, this appears unaffected by radial migration and chemical evolution varying with Galactocentric radius. If confirmed, it points to delayed neutron-capture production beyond neutron star–neutron star mergers.",
  "abstract_shown": true,
  "affiliations": [
    "Max-Planck Institute for Astronomy",
    "Chinese Academy of Sciences"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Meng Zhang",
      "orcid": "0000-0001-9293-131X"
    },
    {
      "affs": [
        0
      ],
      "name": "Hans-Walter Rix",
      "orcid": "0000-0003-4996-9069"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/faptj38d8c238.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4357/ae9f4c",
  "fulltext_url": null,
  "id": "faptj38d8c238",
  "issns": [
    "0004-637X",
    "1538-4357"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae9f4c",
  "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": "W7213239210",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae9f4c/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-30",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/faptj38d8c238.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:11Z",
      "native_id": "10.3847/1538-4357/ae9f4c",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae9f4c"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
    }
  ],
  "title": "Constraining the Delay Time Distribution of the r - and s -process from Stellar Ages at Solar Metallicity",
  "title_text": "Constraining the Delay Time Distribution of the r - and s -process from Stellar Ages at Solar Metallicity",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:11Z",
  "url": "https://research.draconitic.com/paper/faptj38d8c238",
  "venue": "The Astrophysical Journal",
  "versions": [
    {
      "doi": "10.48550/arxiv.2609.15621",
      "pid": "6mdnk4jed8fna",
      "relation": "preprint",
      "title": "Constraining the Delay Time Distribution of the r- and s-Process from Stellar Ages at Solar Metallicity",
      "venue": "arXiv"
    }
  ]
}