{
  "abstract": "An open question in exoplanet science is whether rocky exoplanets extremely close in to their host stars, “lava worlds,” can retain significant atmospheres. Thermal emission observations via secondary eclipse can be used to determine whether a rocky exoplanet possesses an atmosphere. It is expected that an atmosphere could increase the planet’s albedo and/or redistribute heat away from the dayside, reducing the secondary eclipse depth measured. Recent eclipse observations of lava planets, rocky planets hot enough to have liquid magma surfaces, have suggested the presence of atmospheres. Here, we present a single JWST MIRI/LRS partial secondary eclipse of the lava planet TOI-431b. We measure an eclipse depth of 81 ± 16 ppm, which corresponds to a brightness temperature of 196 7 − 253 + 237 K and a brightness temperature ratio R = 0.81 ± 0.10, being 1.2 σ higher than the value reported by Spitzer. The observed brightness temperature ratio is 1.8 σ below that of a zero-albedo, zero heat redistribution bare rock ( R = 1). Given that magma pools are expected to have low albedos, we find that our results are best explained by the presence of an atmosphere. Future work to measure the exact composition of TOI-431b’s atmosphere and improve models of lava planet atmospheres would better constrain the nature and evolution of lava planets.",
  "abstract_shown": true,
  "affiliations": [
    "University of Maryland",
    "University of Chicago",
    "Instituto de Astrofísica de Andalucía (IAA-CSIC)",
    "University of Birmingham",
    "Carnegie Science",
    "Space Telescope Science Institute",
    "Peking University",
    "University of Texas at Austin",
    "Instituto de Astrofísica de Canarias: San Cristobal de La Laguna",
    "Universidad de La Laguna (ULL)"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 16,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Cole Smith",
      "orcid": "0009-0004-1094-3093"
    },
    {
      "affs": [
        1
      ],
      "name": "Brandon Park Coy",
      "orcid": "0000-0002-0508-857X"
    },
    {
      "affs": [
        0
      ],
      "name": "Megan Weiner Mansfield",
      "orcid": "0000-0003-4241-7413"
    },
    {
      "affs": [
        2
      ],
      "name": "Rafael Luque",
      "orcid": "0000-0002-4671-2957"
    },
    {
      "affs": [
        3
      ],
      "name": "Anjali A. A. Piette",
      "orcid": "0000-0002-4487-5533"
    },
    {
      "affs": [
        1
      ],
      "name": "Qiao Xue",
      "orcid": "0000-0002-6215-5425"
    },
    {
      "affs": [
        1
      ],
      "name": "Michael Zhang",
      "orcid": "0000-0002-0659-1783"
    },
    {
      "affs": [
        1
      ],
      "name": "Jacob L. Bean",
      "orcid": "0000-0003-4733-6532"
    },
    {
      "affs": [
        1
      ],
      "name": "Madison Brady",
      "orcid": "0000-0003-2404-2427"
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    {
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        4
      ],
      "name": "Peter Gao",
      "orcid": "0000-0002-8518-9601"
    },
    {
      "affs": [
        5
      ],
      "name": "Jegug Ih",
      "orcid": "0000-0003-2775-653X"
    },
    {
      "affs": [
        1
      ],
      "name": "Eliza M.-R. Kempton",
      "orcid": "0000-0002-1337-9051"
    },
    {
      "affs": [
        1
      ],
      "name": "Edwin Kite",
      "orcid": "0000-0002-1426-1186"
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    {
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        6
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      "name": "Daniel Koll",
      "orcid": "0000-0002-9076-6901"
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    {
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        7
      ],
      "name": "Jaume Orell-Miquel",
      "orcid": "0000-0003-2066-8959"
    },
    {
      "affs": [
        8,
        9
      ],
      "name": "Enric Palle",
      "orcid": "0000-0003-0987-1593"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/87xfka6zw0x99.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-3881/aea574",
  "fulltext_url": null,
  "id": "87xfka6zw0x99",
  "issns": [
    "0004-6256",
    "1538-3881"
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  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-3881/aea574",
  "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": [
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      "openalex",
      "3103|Stellar, planetary, and galactic studies"
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  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-3881/aea574/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/87xfka6zw0x99.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:14Z",
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  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
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  ],
  "title": "JWST MIRI Reveals a Potential Atmosphere on the Ultrahot Rocky Planet TOI-431b",
  "title_text": "JWST MIRI Reveals a Potential Atmosphere on the Ultrahot Rocky Planet TOI-431b",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:14Z",
  "url": "https://research.draconitic.com/paper/87xfka6zw0x99",
  "venue": "The Astronomical Journal",
  "versions": []
}