Examples of the time (t) evolution of temperature (T) and the density (n, see the legend) of all the species in the chemical network. The solid lines represent the solutions computed using KROME, while the dashed lines depict the predictions of our models, with each line being a single solution from the emulator. In the left (right) panel the gas number density is n = 10⁴ cm⁻³ (initial temperature is T = 10⁶ K), namely, outside the range of the training dataset (see Table 2).