{
  "abstract": "Post-perovskite is expected to dominate much of the solid mantles of rocky exoplanets, yet iron partitioning between post-perovskite and silicate melt, which controls the compositional evolution and buoyancy of crystallizing magma oceans, is unconstrained at these pressures. We use first-principles molecular dynamics and thermodynamic integration to compute the Fe--Mg distribution coefficient $K_D$ between post-perovskite and (Mg,Fe)SiO$_3$ liquid at 150--600~GPa and 6000--10000~K. Iron is strongly incompatible in post-perovskite and becomes increasingly so with pressure. Combining $K_D$ with equations of state, we find that iron enrichment of residual liquid reverses the solid--liquid density contrast, causing post-perovskite to become buoyant. Basal magma oceans are therefore gravitationally stable in super-Earth exoplanets up to 4 M$_{\\oplus}$.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.13527",
  "author_total": 2,
  "authors": [
    {
      "name": "Francis Dragulet"
    },
    {
      "name": "Lars Stixrude"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/078n3v1dykqvf.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.13527",
  "fulltext_url": null,
  "id": "078n3v1dykqvf",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.13527",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ],
    [
      "openalex",
      "1908|High-pressure geophysics and materials"
    ]
  ],
  "openalex": "W7213337879",
  "pdf_url": "https://arxiv.org/pdf/2609.13527",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/078n3v1dykqvf.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.13527",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.13527"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "Incompatibility of iron in post-perovskite and the stability of basal magma oceans in super-Earths",
  "title_text": "Incompatibility of iron in post-perovskite and the stability of basal magma oceans in super-Earths",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/078n3v1dykqvf",
  "venue": "arXiv",
  "versions": []
}