FUSE Spectroscopy of the Two Prototype White Dwarfs With Signatures of a   Super-hot Wind
  The O VIII phenomenon describes the occurrence of ultra-high ionization absorption lines of the CNO elements (e.g. O VIII, N VII, C VI, and even Ne X) in the optical spectra hot of DO WDs. 
K. Werner, S. Dreizler, J.W. Kruk, M.L. Sitko