Analysis of Light Curves of Eclipsing Systems with Exoplanets: HD 189733

TL;DR

This study analyzes high-precision multicolor light curves of the HD 189733 system to determine stellar and planetary parameters, confirming wavelength-dependent exoplanet radius variations indicative of an atmosphere.

Contribution

It provides detailed measurements of the star and exoplanet radii, orbital inclination, and limb-darkening coefficients across multiple wavelengths, with comparison to theoretical models.

Findings

Exoplanet radius increases at shorter wavelengths.

Wavelength dependence of limb-darkening coefficients matches theoretical models.

Confirmation of atmospheric presence around the exoplanet.

Abstract

High-accuracy multicolor light curves of the binary system HD 189733, which contains an exoplanet, are analyzed. We have determined the radii of the star and the planet in the binary system, as well as the orbital inclination. The limb-darkening coefficients of the stellar disk were obtained in 10 filters in the wavelength interval 5500-10500 AA. The uncertainties of the fitted parameters were estimated using the differential-correction and confidence-area methods. The wavelength dependence of the limb-darkening coefficients is compared to the corresponding theoretical function for a model thin stellar atmosphere. We confirm the wavelength dependence of the exoplanet's radius found by Pont et al. The exoplanet radius increases with decreasing wavelength, which seems to argue for the presence of an atmosphere around the planet.