{
  "abstract": "We present a study of stellar limb-darkening using JWST transit observations of seven exoplanets orbiting FGK host stars, spanning 4200-6800 K. The wide wavelength coverage and high S/N of NIRISS/SOSS and NIRSpec/PRISM enable precise constraints on the wavelength-dependent limb-darkening. Using Bayesian model selection, we find that the quadratic limb-darkening law is statistically preferred over higher-order laws for most FGK stars, recovers consistent intensity profiles for $>$95% of the stellar disk area, and introduces a minimal bias in the derived transit depths of only $\\sim$14 ppm (1$σ$) for 6/7 targets. This contrasts with previous studies relying on stellar models. We compare the empirically derived quadratic coefficients to predictions from the PHOENIX, MPS-ATLAS, MURaM, and Stagger stellar atmosphere grids. We introduce a quadratic limb-darkening parameterization in terms of limb intensity ($\\ell$) and curvature at mid-$μ$ ($δ$), finding that empirical FGK limb darkening is generally more linear than models predict ($δ\\lesssim 0.1$). We identify wavelength-independent offsets between data and model quadratic coefficients, minimized by adopting $μ_{\\rm min} = 0.2$ in intensity calculations; we attribute this in part to models overpredicting limb-darkening near the limb where the plane-parallel approximation breaks down. For spherical PHOENIX models, we derive a $μ$ rescaling method using a $τ= 1$ photospheric radius. With these corrections, residual offsets are minimized and all stellar models achieve statistically acceptable fits. We provide recommended limb-darkening offset priors for use in JWST transit analyses, enabling more accurate constraints on exoplanet transmission spectra while accounting for residual stellar model uncertainties.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.00263",
  "author_total": 14,
  "authors": [
    {
      "name": "David K. Sing"
    },
    {
      "name": "Joshua D. Lothringer"
    },
    {
      "name": "Jeff A. Valenti"
    },
    {
      "name": "Natalie H. Allen"
    },
    {
      "name": "Katherine A. Bennett"
    },
    {
      "name": "Carlos Gascón"
    },
    {
      "name": "Mei Ting Mak"
    },
    {
      "name": "Patrick McCreery"
    },
    {
      "name": "Sagnick Mukherjee"
    },
    {
      "name": "Lakeisha M. Ramos Rosado"
    },
    {
      "name": "Stephen P. Schmidt"
    },
    {
      "name": "Kevin B. Stevenson"
    },
    {
      "name": "Daniel P. Thorngren"
    },
    {
      "name": "Le-Chris Wang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5bbh4bhepdjq0.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.00263",
  "fulltext_url": null,
  "id": "5bbh4bhepdjq0",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.00263",
  "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.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.00263",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5bbh4bhepdjq0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:00Z",
      "native_id": "2609.00263",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.00263"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "A JWST transiting survey of FGK stellar limb darkening: empirical evidence for quadratic laws and atmospheric model comparisons",
  "title_text": "A JWST transiting survey of FGK stellar limb darkening: empirical evidence for quadratic laws and atmospheric model comparisons",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:00Z",
  "url": "https://research.draconitic.com/paper/5bbh4bhepdjq0",
  "venue": "arXiv",
  "versions": []
}