We present a model to account for the observed debris disks around young white dwarfs and the presence of metal-lines in their spectra. Stellar evolution models predict that the mass-loss on the AGB will be pulsed and furthermore, observations indicate that the bulk of the mass-loss occurs on the AGB. In this case, if the progenitors of the white dwarfs had remnants of planetary formation like the Sun’s Oort cloud or the Kuiper Belt and a planet lying within that cloud or nearby, we find that between 0.06% to 2.3% of the planetesimals will fall either into planet-crossing orbits or into chaotic regions after the mass-loss, depending on the location and mass of the planet (from Mars to Neptune). This yields a sufficient mass of comets that can be scattered toward the star, form a debris disk and pollute the atmosphere.
I. Caiazzo and J. Heyl
Mon, 27 Feb 17
Comments: 9 pages, 5 figures, submitted to MNRAS