New developments of the ZZ Ceti instability strip: The discovery of eleven new variables

Abstract

Using the SOAR 4.1 m telescope, we report on the discovery of low amplitude pulsations for three stars previously reported as Not-Observed-to-Vary (NOV) by Mukadam et al. (2004) and Mullally et al. (2005), which are inside the ZZ Ceti instability strip. With the two pulsators discovered by Castanheira et al. (2007), we have now found variability in a total of five stars previously reported as NOVs. We also report the variability of eight new pulsating stars, not previously observed, bringing the total number of known ZZ Ceti stars to 148. In addition, we lowered the detection limit for ten NOVs located near the edges of the ZZ Ceti instability strip. Our results are consistent with a pure mass dependent ZZ Ceti instability strip.

17 pages, 5 figures

References in corpus (4)

• Seismological studies of ZZ Ceti stars. I. The model grid and the application to individual stars
• Mapping the ZZ Ceti Instability Strip: Discovery of 6 New Pulsators
• Towards a pure ZZ Ceti instability strip
• Gemini spectra of 12000K white dwarf stars

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• Probing the structure of Kepler ZZ Ceti stars with full evolutionary models-based asteroseismology
• Discovery of ZZ Cetis in detached white dwarf plus main-sequence binaries
• New ZZ Ceti stars from the LAMOST survey