Exoplanet Atmosphere Retrieval using Multifractal Analysis of Secondary Eclipse Spectra.

We extend a data-based model-free multifractal method of exoplanet detectionto probe exoplanetary atmospheres. Whereas the transmission spectrum is studiedduring the primary eclipse, we analyze the emission spectrum during thesecondary eclipse, thereby probing the atmospheric limb. In addition to thespectral structure of exoplanet atmospheres, the approach provides informationto study phenomena such as atmospheric flows, tidal-locking behavior, and thedayside-nightside redistribution of energy. The approach is demonstrated usingSpitzer data for exoplanet HD189733b. The central advantage of the method isthe lack of model assumptions in the detection and observational schemes.