Adiabats as functions of compression ratio X and shock speed v1 for γ = 5/3, θ1 = 30°, c1 = 8.958 km s−1, and four values of a1: 6 km s−1 (full blue), c1 = 8.958 km s−1 (long-dashed orange), 12 km s−1 (short-dashed green), and 35 km s−1 (dotted–dashed red).