2 Problem 2 Assume two adjacent interstellar gas clouds with known thickness dị and d2 found in front of an astronomical light source. Suppose that this source emits a beam of radiation with known specific intensity 1, as it enters the first cloud of interstellar gas. Calculate the specific intensity I, immediately after this beam has traversed the two clouds of gas. Assume that the densities (p1 and p2) and the opacities (k,1 and ky,2) are constant within the clouds and are known quantities and that these clouds possess no emissivity. (Note the relationship between the opacity and absorption coefficient a, = pk,. See Rybicki and Lightman eq. 1.22.) %3D

2 Problem 2 Assume two adjacent interstellar gas clouds with known thickness dị and d2 found in front of an astronomical light source. Suppose that this source emits a beam of radiation with known specific intensity 1, as it enters the first cloud of interstellar gas. Calculate the specific intensity I, immediately after this beam has traversed the two clouds of gas. Assume that the densities (p1 and p2) and the opacities (k,1 and ky,2) are constant within the clouds and are known quantities and that these clouds possess no emissivity. (Note the relationship between the opacity and absorption coefficient a, = pk,. See Rybicki and Lightman eq. 1.22.) %3D