"From Exoplanets to Extreme Physics and Back, a Walk With White Dwarfs"

 

Professor Don Winget
Department of Astronomy, UT Austin

 

 The ZZ Ceti Stars are a class of pulsating white dwarf stars. The hottest of these pulsators are the most stable optical clocks in the sky. We monitor these clocks, searching for the signature of their secular evolution or the presence of extra-solar planetary companions. The latter will produce light-travel time effects as the pulsations arrive earlier and later due to the reflex orbital motion of the parent star. This method of planet detection is sensitive to the acceleration, not the velocity, of the parent star; this results in a gain in sensitivity relative to the Doppler spectroscopic method -- the method responsible for most of the planet discoveries to date.
We are unique among current searches in that planetary systems dynamically similar to our own solar system are the easiest for us to detect. I will report our best current case for a planetary mass companion around a white dwarf. Planetary companions or no, we will be able to measure the evolutionary timescales for the entire sample of stars; these results will allow us to measure plasmon neutrino production in white dwarf interiors, as well as set constraints on astrophysically interesting axion production -- promising candidates for dark matter. I will also present and discuss our group's recent detections, with the Spitzer Space Telescope and IRTF, of debris disks around a subset of white dwarf stars. These discoveries also have implications for the existence of planetary systems around white dwarf stars.