Infrared Variability around Planetesimal-eating White Dwarfs

Monday, 15 April 2019 9 a.m. — 10 a.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
LAURA ROGERS (University of Cambridge and Gemini South Visiting Astronomer)

Evidence for the survival of outer planetary systems to the white dwarf phase comes from observations of planetary material polluting the atmospheres of white dwarfs. These observations are unique in providing the composition of exo-planetary material. Infrared observations of dust very close to white dwarfs reveal how planetary material arrives in the atmospheres of white dwarfs. We expect the scattering of planetary bodies that leads to pollution to be a stochastic process, with the potential for variability on human timescales. Such variability has been found for the white dwarf WD J0959-0200 among others, where a drop in K band flux of 20% was observed within one year. I present the results from a large scale near-infrared monitoring campaign of ~80% of all known dusty white dwarfs using UKIRT (WFCAM) over a baseline of 3 years.