Eleven New DAVs from the Sloan Survey
  We report the discovery of eleven new variable DA white dwarf (ZZ Ceti) stars. Candidates were selected by deriving temperatures from model fits to spectra obtained from the Sloan Digital Sky Survey. We also find objects whose temperatures and gravities indicate they lie within the instability strip for pulsation, but which were not observed to vary. Although the temperatures are based on relatively low S/N spectra, an impure strip is unexpected, and if confirmed suggests that our knowledge of the pulsation mechanism is incomplete. This work brings the total number of published variable DA white dwarf stars to 82. 
F. Mullally, S. E. Thompson, B. G. Castanheira, D. E. Winget, S. O.   Kepler, D. J. Eisenstein, S. J. Kleinman and Atsuko Nitta