1996A&A...310..106P

The chemical evolution of deuterium and helium-3 in the disk of our Galaxy is studied with numerical models assuming infall. It is shown that, in the framework of our models, the current D gradient is considerably steeper than the corresponding oxygen gradient and very sensitive to the assumed history of infall. Combined to forthcoming observations of the D abundance across the galactic disk, those results can be used to derive information on the formation history of the Milky Way. The ³He abundance profile is found to be less sensitive to the details of the chemical evolution model; it depends essentially on the, still not quite well understood, nucleosynthesis of that isotope in low-mass stars.