Peak temperatures (K) of the rotational emission lines of SiO, relative to the J = 5–4 transition, as functions of the rotational quantum number of the upper level of the transition J_up. Displayed are the shock models in our grid that are most strongly influenced by vaporization, i.e. V_s = 20 km s^-1 with b = 1 (blue), V_s = 30 km s^-1 with b = 1.5 (green), and V_s = 40 km s^-1 with b = 2 (red). Full lines: M1; dotted lines: M2; broken lines: M3.