Résumé
Aims. Observations show nebulae around some massive stars but not around
others. If observed, their chemical composition is far from homogeneous. Our
goal is to put these observational features into the context of the evolution
of massive stars and their circumstellar medium (CSM) and, more generally, to
quantify the role of massive stars for the chemical and dynamical evolution of
the ISM. Methods. Using the A-MAZE code, we perform 2d-axisymmetric
hydrodynamical simulations of the evolution of the CSM, shaped by stellar
winds, for a whole grid of massive stellar models from 15 to 120 Msun and
following the stellar evolution from the zero-age main-sequence to the time of
supernova explosion. In addition to the usual quantities, we also follow five
chemical species: H, He, C, N, and O. Results. We show how various quantities
evolve as a function of time: size of the bubble, position of the wind
termination shock, chemical composition of the bubble, etc. The chemical
composition of the bubble changes considerably compared to the initial
composition, particularly during the red-supergiant (RSG) and Wolf-Rayet (WR)
phases. In some extreme cases, the inner region of the bubble can be completely
depleted in hydrogen and nitrogen, and is mainly composed of carbon, helium and
oxygen. We argue why the bubble typically expands at a lower rate than
predicted by self-similarity theory. In particular, the size of the bubble is
very sensitive to the density of the ISM, decreasing by a factor of around 2.5
for each additional dex in ISM density. The bubble size also decreases with the
metallicity of the central star, as low-metallicity stars have weaker winds.
Our models qualitatively fit the observations of WR ejecta nebulae.