{
  "abstract": "Recent JWST observations have revealed that the morning and evening limbs of the hot Jupiter WASP-94Ab have very different transmission spectra. An analysis of these resolved limb spectra yielded a metallicity more than an order of magnitude below that obtained from the limb-averaged spectrum, which calls into question the accuracy of traditional retrievals for heterogenous planets. Here we analyze the limb-averaged JWST NIRISS and NIRSpec transmission spectra of WASP-94Ab using both a standard one-temperature-profile (1-TP) retrieval with patchy clouds, and a new two-temperature-profile (2-TP) retrieval. The 2-TP retrieval assumes a linear combination of two atmospheric components that share the same bulk elemental composition but have independent thermal structures, chemistries, and aerosol properties. This model is implemented in PLATON 7.0, a JAX-accelerated code that is over 100 times faster than its predecessor, which is key to making the retrieval computationally tractable. The limb-averaged spectrum of WASP-94Ab favors the 2-TP model by a Bayes factor K=1.8x10^{5} and shifts the metallicity downward to Zatm/Zsun = 11^{+9}_{-4} from 170^{+30}_{-24} obtained with the 1-TP model. The 2-TP retrieval predicts two, equally weighted components that reproduce the limb-resolved spectra across both instruments without prior knowledge of them. This work demonstrates that compositional information survives limb averaging for WASP-94Ab, suggesting that 2-TP retrievals can be used to identify limb-asymmetry and extend metallicity studies beyond the small set of planets amenable to limb-resolved spectroscopy.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.20923",
  "author_total": 8,
  "authors": [
    {
      "name": "Tyler R. Fairnington"
    },
    {
      "name": "Michael Radica"
    },
    {
      "name": "Michael Zhang"
    },
    {
      "name": "Eliza M. -R. Kempton"
    },
    {
      "name": "Jacob L. Bean"
    },
    {
      "name": "Eva-Maria Ahrer"
    },
    {
      "name": "Arjun B. Savel"
    },
    {
      "name": "Pascal S. D'Andrea"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8kcnwrj6453tn.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.20923",
  "fulltext_url": null,
  "id": "8kcnwrj6453tn",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.20923",
  "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.EP"
    ],
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7213900982",
  "pdf_url": "https://arxiv.org/pdf/2609.20923",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8kcnwrj6453tn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:03Z",
      "native_id": "2609.20923",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.20923"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "Recovering the Morning and Evening Limbs of WASP-94Ab from Its Limb-Averaged JWST Transmission Spectrum",
  "title_text": "Recovering the Morning and Evening Limbs of WASP-94Ab from Its Limb-Averaged JWST Transmission Spectrum",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:03Z",
  "url": "https://research.draconitic.com/paper/8kcnwrj6453tn",
  "venue": "arXiv",
  "versions": []
}