Spectral Analyses of DO White Dwarfs and PG1159 Stars from the Sloan   Digital Sky Survey
  SDSS (DR1 and DR2) has recently proposed 7 new DO white dwarfs as well as 6 new PG1159 stars. This is a significant increase in the known number of DOs and PG1159 stars. Our spectral analyses provide stellar parameters which can then be used to derive constraints for the evolution of H-deficient white dwarfs. A comprehensive understanding of these objects is still severely hampered by low-number statistics. 
S. D. Huegelmeyer (1), S. Dreizler (1), K. Werner (2), A. Nitta (3),   S. J. Kleinman (3), J. Krzesinski (3) ((1) Institut f...