Fig. 3.

Profiles of the impact parameter, b, refraction angle, ω, and the refractive loss factor, $f_{\text{ref}}$, from our Titan ray-tracing model. The vertical coordinate is the ray’s altitude of closest approach, $z_{\text{min}}$. Parameters are shown for a wavelength of 5 μm, where Titan’s atmospheric haze is least opaque, and we use a distance, D, from the spacecraft to Titan of 8,400 km, appropriate for the 27° N occultation, when computing the refractive loss. The dotted line plots along the diagonal, and shows that the impact parameter is always larger than the distance of closest approach.