News from Low Mass Star Nucleosynthesis and Mixing
  Light and intermediate nuclei as well as s-process elements have been
detected in presolar grains and in evolved red giants. The abundances of some
of these nuclei cannot be accounted for by canonical stellar models and require
non-convective mixing below the envelope, occurring during the phases of the
Red Giant Branch (RGB) and of the Asymptotic Giant Branch (AGB). Similar
mechanisms appear to be necessary to account for the formation of the neutron
source driving s processing. We present a short review of these phenomena and
we comment on the picture that emerges from the set of available data on the
evolution and nucleosynthesis in low mass stars. Our conclusions include: i)
the need for deep mixing in both RGB and AGB stars; ii) the suggestion that
these phenomena occur at a non-negligible velocity, possibly incompatible with
diffusive processes; iii) the verification that the abundances of neutron-rich
nuclei are presently increasing in the Galaxy, contrary to previous
expectations and hence that the s process has new surprises to offer us; iv)
the recognition of the growing importance of very low mass stars for Galactic
nucleosynthesis.
