Cooling time vs. temperature given the cooling function of N. Y. Gnedin & N. Hollon (2012). After the shell forms at a temperature of 2.5 × 10⁵ K, the shell will rapidly cool to 10⁴ K and remain at this temperature on the order of ≈1 Myr or more. Given that shell formation occurred t_sf = 0.97 Myr ago and the CLIC’s current temperature of 5000−10,000 K, the predicted cooling is in agreement with our model for the shell evolution and the observed thermal properties of the CLIC.