Cu and Zn in different stellar populations: Inferring their astrophysical origin

Abstract. We analyse recent high-resolution spectroscopic observations of Cu and Zn for stars of different stellar populations and metallicities, using the best available stellar nu-cleosynthesis expectations. The observations include unevolved stars of the Galactic halo, thick-disk and thin-disk, bulge-like stars and stars of Ω Cen, globular clusters and Dwarf Spheroidal systems. Most cosmic Cu and half the Zn are synthesised in massive stars during the hydrostatic He-burning and C-burning phases by the weak sr-process, which depends linearly on metallicity. A minor primary contribution for Cu derives from explosive nucle-osynthesis in SNe II. A large primary contribution to Zn (as 64Zn) is ascribable to the α-rich freezout in ν-winds or to SNe II with large explosion energies (hypernovae). AGB stars and type Ia supernovae do not contribute appreciably to either Cu or Zn. 1