Abstract

Understanding radiative transfer is an integral part of predicting synthetic spectra from exoplanetary atmospheres and also interpreting measured spectra of them. A commonly used technique is two-stream radiative transfer, which approximates the passage of radiation as a pair of outgoing and incoming fluxes. I will demonstrate that the two-stream solutions, the diffusion approximation and analytical temperature-pressure profiles all originate from the same set of governing equations, implying that the values of the Eddington coefficients adopted need to be self-consistent across all three treatments. Surprisingly, the Eddington closure produces unphysical effects and should be avoided. I will briefly discuss applications: computing synthetic spectra, the runaway greenhouse effect and detached convective regions.