younger family members. For these EGPs, either the large residual heat coming from the core or the severe insolation prop up the fluxes from 1 to 4 . The more massive EGPs, or, for a given mass, the younger EGPs, have larger $J$, $H$, and $K$ band fluxes. As a result, these bands are diagnostic of mass and age. For EGPs with large orbital distances, the wavelength range from 1.5 to 4 between the reflection and emission components may be the least favorable search space, unless the SMO is massive or young.

When water or ammonia clouds form, scattering off them enhances the optical fluxes, while absorption by them suppresses fluxes at longer wavelengths in, for example, the 4–5 window. Because water and ammonia clouds form in the middle of this distance sequence, the reflection efficiency (or “albedo"; §\[phase\]) is not a monotonic function of $a$. These effects are incorporated into Fig. 2, but their precise magnitude depends upon unknown cloud particle size, composition, and patchiness. As a consequence, direct spectral measurements might constrain cloud properties.

Importantly, trace non-equilibrium molecular species, difficult to model, can be present in quantities sufficient to alter colors. Such a “chromophore," whose molecular nature is 