Production of Light Element Primary Process nuclei in neutrino-driven
  winds
  We present first comparisons between Light Element Primary Process (LEPP)
abundances observed in some ultra metal poor (UMP) stars and nucleosynthesis
calculations based on long-time hydrodynamical simulations of core-collapse
supernovae and their neutrino-driven wind. UMP star observations indicate Z>38
elements include the contributions of at least two nucleosynthesis components:
r-process nuclei that are synthesized by rapid neutron capture in a yet unknown
site and LEPP elements (mainly Sr, Y, Zr). We show that neutrino-driven wind
simulations can explain the observed LEPP pattern. We explore in detail the
sensitivity of the calculated abundances to the electron fraction, which is a
key nucleosynthesis parameter but poorly known due to uncertainties in neutrino
interactions and transport. Our results show that the observed LEPP pattern can
be reproduced in proton- and neutron-rich winds.
