Dust optical depth
= Dust optical depth
{title2=$\tau_d$}
For dust-grain number density $n_d$ and absorption cross-section $\sigma_d$, the dust optical depth along a path is $\tau_d=\int n_d\sigma_d\,ds$.
= Dust optical depth
{title2=$\tau_d$}
For dust-grain number density $n_d$ and absorption cross-section $\sigma_d$, the dust optical depth along a path is $\tau_d=\int n_d\sigma_d\,ds$.