Enrichment of the r-process element europium in the Galactic halo

We investigate the enrichment of europium, as a representative of r-process elements, in the Galactic halo. In present chemical evolution models, star s are assumed to be formed through shock processes by supernovae (SNe). The enrichment of the interstellar medium is calculated by a one-zone approach . The observed large dispersions in [Eu/Fe] for halo stars, converging with increasing metallicity, can be explained with our models. In addition, the mass range of SNe for the r-process site is constrained to be either stars of 8-10 or greater than or similar to 30 M..