The simulation of infrared spectra towards HII regions

Massive stars form regions of ionized hydrogen (HII) around themselves. Expanding over time, HII regions have a significant effect on the interstellar medium. Important information about the structure of these objects is provided by observations in the infrared (IR) range, however, the interpretation of the IR spectra remains challenging, due to a wealth of physical processes, which are responsible for the formation of the IR spectrum. We investigate how the IR emission spectrum of the considered volume inside the HII region depends on its distance to the star, and on the abundance of PAH particles in the total mass of dust. We present also the results of IR simulations based on our chemo-dynamical model of the HII region.