(Top) Transmission spectra of a Jupiter-mass planet with a CPDR. Different colored lines show the spectra for different ring surface densities. We assume optical properties of SiO₂ with a mean particle size and size distribution width of the CPDR as a _r = 0.1 μm and σ = 0.5. The ring’s inclination and width are fixed to ϕ = 30 deg and W = 0.5. (Middle) The same as the top panel, but with a different vertical scale. (Bottom) The normal optical depth of the ring. The gray dashed and dotted lines denote the optical depth of 1 and 10⁻³ to indicate the optically thin regime.