Research Division Seminar
IAU G5 seminar: " How White Dwarfs Get Their Metals"
Dr. Scott Kenyon
Many (perhaps most) nearby white dwarfs have strong
absorption lines from Ca, Si, Mg, Al, and other metals
on optical and ultraviolet spectra. Abundance analyses
suggest the ensemble of metals has a composition similar
to asteroids or the cores of rocky planets. The atmospheric
diffusion times are much smaller than their ages. Thus, the
metals must be continually replenished. I will describe
observations of these systems and outline an evolutionary
path that allows material from an erstwhile planetary system
to end up on the surface of the white dwarf remnant of an
A-type main sequence star.