Oxygen abundances in carbon-type Wolf-Rayet stars from PACS scan spectroscopy

We seek 13.6 hours of spectral scans of the OIII 88 micron finestructure line with PACS for a sample of Milky Way carbon and oxygen sequence WolfRayet stars. The proposed observations will: (i) enable reliable oxygen abundances to be determined for WC stars for the first time, to test evolutionary predictions; (ii) refine the degre of clumpig in the outer stellar winds of these stars derived from existing ISO/SWS or Spitzer/IRS datasets.