Thermal stability of wind near a hot star

We present computations of the ionization and thermal balance in the wind from WR and OB stars. The star’s radiation field is modeled using a Planck function with a temperature from 2 to 6 eV. We assume that the principal contribution from gas heating and cooling is from ions and atoms of hydrogen, carbon, nitrogen, oxygen, and neon. We take into account photoionization from the ground state and excited states, ionization by electron collisions, radiative and two-electron recombination, and excitation and de-excitation of discrete levels by the star’s dilute radiation and electron collisions. It is demonstrated that the thermal regime of gas in the conditions typical of the winds near WR and OB stars is stable.