Claret, A and Southworth, J (2022) Power-2 limb-darkening coefficients for the uvby, UBVRIJHK, SDSS ugriz, Gaia, Kepler, and TESS photometric systems. Astronomy & Astrophysics, 664. ISSN 1432-0746

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Context. Limb darkening is an important stellar phenomenon and must be accounted for in the study of stellar spectra, eclipsing binaries, transiting planetary systems, and microlensing events. The power-2 limb-darkening law provides a good match to the specific intensities predicted by stellar atmosphere models: it is better than other two-parameter laws and is only surpassed by the four-parameter law.

Aims. Predictions of the limb-darkening coefficients for the power-2 law are not widely available. We therefore compute them, using stellar atmosphere models generated by the ATLAS (plane-parallel) code.

Methods. Limb-darkening coefficients were computed for the space missions Gαiα, Kepler, and TESS as well as for the photometric systems uvby, UBVRIJHK, and SDSS ugriz. The calculations were performed by adopting the Levenberg–Marquardt least-squares minimisation method and were computed with a resolution of 100 equally spaced viewing angles. We used 9586 model atmospheres covering 19 metallicities, effective temperatures of 3500–50 000 K, log g values from 0.0 to 5.0, and microturbulent velocities of 0, 1, 2, 4, and 8 km s-1.

Results. We confirm the superiority of the power-2 law, in terms of the quality of the fits, over other two-parameter laws. This is particularly relevant for the quadratic law, which is widely used.

Conclusions. We recommend the use of the power-2 law in cases where a two-parameter law is needed.

Item Type: Article
Additional Information: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe-to-Open model. Subscribe to A&A to support open access publication.
Subjects: Q Science > QA Mathematics
Q Science > QB Astronomy
Q Science > QB Astronomy > QB460 Astrophysics
Q Science > QB Astronomy > QB600 Planets. Planetology
Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 28 Sep 2022 10:33
Last Modified: 28 Sep 2022 10:34

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