Abstract

The Frequency Stability of the Pulsating White Dwarf L19-2

Denis Sullivan (Victoria University of Wellington)

Paul Chote (Victoria University of Wellington)

The hydrogen atmosphere DA white dwarf L19-2 has been proven to be a very stable pulsator. We now have access to nearly four decades of time series photometry on this star, including a Whole Earth Telescope run on the object in 1995, and more recent observations made using the Puoko-nui South CCD photometer on the one metre telescope at Mt John University Observatory in NZ. The brightness of the star combined with its southern declination (-81 degrees) makes it a suitable backup object for southern hemisphere observing plans, and this is the origin of much of our time series data. This DAV white dwarf has two pulsation modes that are suitable for measuring the Pdot values, predicted to arise from evolutionary cooling, and we will present our latest analysis.

Mode of presentation: oral