J/A+A/616/A39ivo://CDS.VizieR/J/A+A/616/A39doi:10.26093/cds/vizier.36160039CDSMaxted P.F.L.2018-09-26T07:09:29Z2018-08-10T12:38:00ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.freclipsing-binary-starsastronomical-modelsstellar-atmospheresInaccurate 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. 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. 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.2018A&A...616A..39Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/616/A39CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/573/A90 : STAGGER-grid of 3D stellar models. IV. (Magic+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/616/A39https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/616/A39http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/616/A39https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/616/A39https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/616/A39http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/616/A39GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/616/A39/table1Specific intensity as function of murecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXBandpassmeta.id;photcharTeffEffective temperatureKphys.temperature.effectivefloatloggLogarithm of surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]Metallicity [Fe/H]phys.abund.ZfloatI(0.00)Specific intensity I_{lambda}_({mu}=0.00)spect.line.intensityfloatI(0.01)Specific intensity I_{lambda}_({mu}=0.01)spect.line.intensityfloatI(0.05)Specific intensity I_{lambda}_({mu}=0.05)spect.line.intensityfloatI(0.10)Specific intensity I_{lambda}_({mu}=0.10)spect.line.intensityfloatI(0.20)Specific intensity I_{lambda}_({mu}=0.20)spect.line.intensityfloatI(0.30)Specific intensity I_{lambda}_({mu}=0.30)spect.line.intensityfloatI(0.50)Specific intensity I_{lambda}_({mu}=0.50)spect.line.intensityfloatI(0.70)Specific intensity I_{lambda}_({mu}=0.70)spect.line.intensityfloatI(0.80)Specific intensity I_{lambda}_({mu}=0.80)spect.line.intensityfloatI(0.90)Specific intensity I_{lambda}_({mu}=0.90)spect.line.intensityfloatI(1.00)Specific intensity I_{lambda}_({mu}=1.00)spect.line.intensityfloatJ/A+A/616/A39/table2Optimized power-2 limb-darkening law parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXBandpassmeta.id;photcharTeffEffective temperatureKphys.temperature.effectivefloatloggLogarithm of surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]Metallicity [Fe/H]phys.abund.Zfloatcc parameterphot.limbDarkfloatalpha{alpha} parameterphot.limbDarkfloath1h_1_ (=1-c(1-2^(-{alpha})^) parameterphot.limbDarkfloath2h_2_ (=c2^(-{alpha}^) parameterphot.limbDarkfloat