Nano-diamond temperatures for HR 4049 (top), Elias 1 (middle), and HD 97048 (bottom) as a function of particle radius (0.5, 1, 3, 10, 30, and 100 nm: red, orange, yellow, green, blue, and violet lines, respectively) and distance from the central star (left panels). Note the different position axis values for HD 97048. The thinner lines are for non-irradiated diamond, and the solid, long-dashed and short-dashed lines are for fully hydrogenated, 75% de-hydrogenated, and fully de-hydrogenated nano-diamond surfaces. The right-hand panels show the relative nano-diamond emission per unit volume 10 AU from the star, or 50 AU from the star in the case of HR 4049.