Features in the Broadband Eclipse Spectra of Exoplanets: Signal or Noise?

Understand

A planet's emission spectrum contains information about atmospheric composition and structure.

• We compare the Bayesian Information Criterion (BIC) of blackbody fits and idealized spectral retrieval fits for the 44 planets with published eclipse measurements in multiple thermal wavebands, mostly obtained with the Spitzer Space Telescope.
• The evidence for spectral features depends on eclipse depth uncertainties.
• Spitzer has proven capable of eclipse precisions better than 1E-4 when multiple eclipses are analyzed simultaneously, but this feat has only been performed four times.