A HIFI view on circumstellar H₂O in M-type AGB stars: radiative transfer, velocity profiles, and H₂O line cooling

Abstract

Aims. We aim to constrain the temperature and velocity structures, and H2O abundances in the winds of a sample of M-type asymptotic giant branch (AGB) stars. We further aim to determine the effect of H2O line cooling on the energy balance in the inner circumstellar envelope.