{
  "abstract": "A growing number of transiting exoplanets exhibit spectroscopic evidence that their leading and trailing limbs differ. Interpreting these observations is now the limiting step. The standard approach of fitting limb-resolved transit depths results in highly anti-correlated transit depths, and treating them as independent measurements can result in strongly biased ($3σ$) retrieved molecular abundances. We present an inference framework that avoids these correlations by using the temporal signature of limb asymmetry instead. This wavelength-dependent shift in mid-transit time, or `time-shift spectrum', carries the limb-asymmetry information, is measurable from existing light curves with a spherically symmetric transit model, and is uncorrelated with the spherically-averaged transit depth. Simultaneously fitting the resulting transmission and time-shift spectrum with an independent atmospheric column for each limb enables the retrieval of limb-resolved properties from two independent measurements. We demonstrate that this approach reduces the mean squared error on the retrieved molecular abundances by factors of $\\sim30-50$ relative to next best of the alternative approaches currently adopted in the field, and improves retrieved abundance precision by $\\sim3-6\\times$. We apply the framework to WASP-94A b and present its panchromatic limb-resolved spectrum, spanning 0.8-5~$μ$m and combining NIRISS/SOSS and NIRSpec/G395H observations. The planet's morning limb remains aerosol-obscured across this entire range, while its evening limb constrains the abundances of H$_2$O, CO$_2$, CO, and H$_2$S. We measure a limb-to-limb temperature difference of $415\\pm58$~K at 1~mbar. This limb-resolved analysis finds [M/H]=+0.32$^{+0.11}_{-0.11}$ and C/O=0.724$^{+0.013}_{-0.013}$, consistent with the host star.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.22271",
  "author_total": 5,
  "authors": [
    {
      "name": "Sagnick Mukherjee"
    },
    {
      "name": "Luis Welbanks"
    },
    {
      "name": "Guangwei Fu"
    },
    {
      "name": "David K. Sing"
    },
    {
      "name": "Michael R. Line"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/den2mjbepraaf.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.22271",
  "fulltext_url": null,
  "id": "den2mjbepraaf",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.22271",
  "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"
    ],
    [
      "arxiv",
      "astro-ph.IM"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.22271",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/den2mjbepraaf.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2610.22271",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.22271"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "A New Method for Constraining 3D Exoplanet Atmospheres: Application to WASP-94A b's Panchromatic Spectrum",
  "title_text": "A New Method for Constraining 3D Exoplanet Atmospheres: Application to WASP-94A b's Panchromatic Spectrum",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/den2mjbepraaf",
  "venue": "arXiv",
  "versions": []
}