Mapping the ZZ Ceti Instability Strip: Discovery of Six New Pulsators

Abstract

As part of an ongoing program to better map the empirical instability strip of pulsating ZZ Ceti white dwarfs, we present a brief progress report based on our last observing season. We discuss here high-speed photometric measurements for six new pulsators. These stars were selected on the basis of preliminary measurements of their effective temperatures and surface gravities, which placed them inside or near the known ZZ Ceti instability strip. We also report detection limits for a number of DA white dwarfs that showed no sign of variability. Finally, we revisit the ZZ Ceti star G232-38, for which we obtained improved high-speed photometry.