Effect of grain size on band shape. The top panel shows the profile of the 69 μm forsterite band at 150 K for different grain sizes. The profiles were computed using the optical constants from Suto et al. (2006) and the distribution of hollow spheres (Min et al. 2003). The lower panel shows the relation between peak position and FWHM of the profiles shown in the top panel. The asterisks in the lower panel correspond to the grain sizes in the upper panel, starting with 1 μm at the bottom.