Temperatures circumstellar shells

However, as temperatures and densities drop steeply in the circumstellar shell with increasing distance from the central star, reaction kinetics may no longer permit establishment of thermochemical equilibrium in the stellar outflow 4). Detailed and generally applicable discussions of the reaction kinetics relevant here can be found in 52, 53). Let us follow a parcel of hot atmospheric gas traveling away from the photosphere and assume that a certain gas is produced or destroyed by some reaction in the CSE. As long as chemical... 

At temperatures and densities of circumstellar shells, the chemistry is in general likely to be highly non-equilibrium. However, in the hotter and denser Inner parts of stellar winds, oiroumstellar shells and in particular cool stellar atmospheres, equilibrium chemistry may be a reasonable approximation, and can at least give us a basis from which non-equillbrium chemistry could be considered. 

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