Rogue Waves on Pulsating White Dwarf Stars

JJ Hermes, University of North Carolina, Chapel Hill

           While it has been an efficient planet-discovery machine, the unblinking stare of the Kepler space telescope has also revolutionized the way we look at pulsating stars. I will discuss some of the rapid advances Kepler has enabled in our understanding of stars at the end of their life cycles -- white dwarf stars -- including a completely unexpected new physical phenomenon: large-amplitude outbursts in the coolest pulsating white dwarfs. These outbursts are essentially rogue waves, sporadically increases the overall stellar brightness by up to 15%. The outbursts have provided fresh insight into how pulsation energy can be transferred through nonlinear resonances, as well as the eventual cessation of pulsations in cool white dwarfs.