Identification of gravity modes in the newly discovered ZZ Ceti variable GD 66.

The authors report the discovery of a new ZZ Ceti variable: GD66. The star was selected from spectrophotometric data obtained with the Hale Double Spectrograph. Its colors in the MCSP system place GD66 in the ZZ Ceti instability strip. Fast photometry confirms the variability of GD66. Four periods are identified with 304s, 273s, 256s and 197s periods. The fact that the Fourier spectrum consists of three closely spaced frequencies separated from a fourth frequency, leads to a tentative identification of the observed modes. The periods and the effective temperature also suggest that GD66 is a massive white dwarf with a large mass hydrogen outer layer. A stratified DA model is computed with these parameters.