Chemical evolution with rotating massive star yields: I. The solar
  neighbourhood and the s-process elements
  We present a comprehensive study of the abundance evolution of the elements
from H to U in the Milky Way halo and local disk. We use a consistent chemical
evolution model, metallicity dependent isotopic yields from low and
intermediate mass stars and yields from massive stars which include, for the
first time, the combined effect of metallicity, mass loss and rotation for a
large grid of stellar masses and for all stages of stellar evolution. The
yields of massive stars are weighted by a metallicity dependent function of the
rotational velocities, constrained by observations as to obtain a primary-like
$^{14}$N behavior at low metallicity and to avoid overproduction of s-elements
at intermediate metallicities. We show that the solar system isotopic
composition can be reproduced to better than a factor of two for isotopes up to
the Fe-peak, and at the 10\% level for most pure s-isotopes, both light ones
(resulting from the weak s-process in rotating massive stars) and the heavy
ones (resulting from the main s-process in low and intermediate mass stars). We
conclude that the light element primary process (LEPP), invoked to explain the
apparent abundance deficiency of the s-elements with A< 100, is not necessary.
We also reproduce the evolution of the heavy to light s-elements abundance
ratio ([hs/ls]) - recently observed in unevolved thin disk stars - as a result
of the contribution of rotating massive stars at sub-solar metallicities. We
find that those stars produce primary F and dominate its solar abundance and we
confirm their role in the observed primary behavior of N. In contrast, we show
that their action is insufficient to explain the small observed values of
C12/C13 in halo red giants, which is rather due to internal processes in those
stars.
