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Table · dataset · 2018

Power-2 limb-darkening law from STAGGER-grid

Listed in IVOA Registry (Virtual Observatory)

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, particularly for high-precision light curves at optical wavelengths.

Description

The power-2 limb-darkening law, I_{lambda}_({mu})=1-c(1-{mu}^{alpha}^), has recently been proposed as a good compromise between complexity and precision in the treatment of limb-darkening.

My aim is to develop a practical implementation of the power-2 limb-darkening law and to quantify the accuracy of this implementation. I have used synthetic spectra based on the 3D stellar atmosphere models from the Stagger-grid to compute the limb- darkening for several passbands (UBVRI, CHEOPS, TESS, Kepler, etc.). The parameters of the power-2 limb-darkening laws are optimized using a least-squares fit to a simulated light curve computed directly from the tabulated I_{lambda}_({mu}) values.

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I use the transformed parameters h_1_=1-c(1-2^(-{alpha})^) and h_2_=c2^(-{alpha}^) to directly compare these optimized limb-darkening parameters to the limb darkening measured from Kepler light curves of 16 transiting exoplanet systems. The posterior probability distributions (PPDs) of the transformed parameters h_1_ and h_2_ resulting from the light curve analysis are found to be much less strongly correlated than the PPDs for c and {alpha}.

The agreement between the computed and observed values of (h_1_, h_2_) is generally very good but there are significant differences between the observed and computed values for Kepler-17, the only star in the sample that shows significant variability between the eclipses due to magnetic activity (star spots). The tabulation of h_1_ and h_2_ provided here can be used to accurately model the light curves of transiting exoplanets.

I also provide estimates of the priors that should be applied to transformed parameters h_1_ and h_2_ based on my analysis of the Kepler light curves of 16 stars transiting exoplanets.

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IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/a+a/616/a3911 d agoJSON v1
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concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
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