s-process Enrichment in the Planetary Nebula NGC 3918
  We present deep, high-resolution (R~40000) UVES at VLT spectrophotometric data of the planetary nebula NGC 3918. This is one of the deepest spectra ever taken of a planetary nebula. We have identified and measured more than 700 emission lines and, in particular, we have detected very faint lines of several neutron-capture elements (s-process elements: Kr, Xe and Rb) that enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up. 
J. Garc\'ia-Rojas (1,2), S. Madonna (1,2), V. Luridiana (1,2), N. C.   Sterling (3), C. Morisset (4) ((1) IAC, Spain, (2) De...
astro-ph.SR