Simplified visualization of the modeling setup of sunbather. The variables are as follows: R_p and M_p are the planet radius and mass, a is the orbital distance (only circular orbits are possible), M_* and F_*(λ) are the stellar mass and spectral energy distribution, T₀ and $\dot{M}$ are the (constant) temperature and mass-loss rate of the Parker wind, Z denotes the atmospheric bulk composition, μ(r), ρ(r), υ(r), and T(r) are the atmospheric mean particle mass, density, velocity, and (nonconstant) temperature profiles, n_X(r) represents the number density of any “chemical species” (i.e., any energy level of an atom or ion), b and ϕ are the planet transit impact parameter and orbital phase, and R_*, u₁ (λ) and u₂(λ) are the stellar radius and quadratic limb-darkening parameters.