Maxted, PFL (2023) Limb darkening measurements from TESS and Kepler light curves of transiting exoplanets. Monthly Notices of the Royal Astronomical Society, 519 (3). pp. 3723-3735. ISSN 0035-8711

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Inaccurate limb-darkening models can be a significant source of error in the analysis of the light curves for transiting exoplanet and eclipsing binary star systems. To test the accuracy of published limb-darkening models, I have compared limb-darkening profiles predicted by stellar atmosphere models to the limb-darkening profiles measured from high-quality light curves of 43 FGK-type stars in transiting exoplanet systems observed by the Kepler and TESS missions. The comparison is done using the parameters h′1=Iλ(2/3) and h′2=h′1−Iλ(1/3)⁠, where Iλ(μ) is the specific intensity emitted in the direction μ, the cosine of the angle between the line of sight and the surface normal vector. These parameters are straightforward to interpret and insensitive to the details of how they are computed. I find that most (but not all) tabulations of limb-darkening data agree well with the observed values of h′1 and h′2⁠. There is a small but significant offset Δh′1≈0.006 compared to the observed values that can be ascribed to the effect of a mean vertical magnetic field strength ≈100 G that is expected in the photospheres of these inactive solar-type stars but that is not accounted for by typical stellar model atmospheres. The implications of these results for the precision of planetary radii measured by the PLATO mission are discussed briefly.

Item Type: Article
Additional Information: © The Author(s) 2022. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Uncontrolled Keywords: methods: data analysis; planets and satellites: fundamental parameters; stars: atmospheres; stars: solar-type
Subjects: Q Science > QB Astronomy
Q Science > QB Astronomy > QB460 Astrophysics
Q Science > QB Astronomy > QB600 Planets. Planetology
Q Science > QB Astronomy > QB799 Stars
Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 19 Jan 2023 16:22
Last Modified: 13 Apr 2023 08:17

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