THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS

Abstract

It has long been suspected that metal polluted white dwarfs (types DAZ, DBZ,\nand DZ) and white dwarfs with dusty disks possess planetary systems, but a\nspecific physical mechanism by which planetesimals are perturbed close to a\nwhite dwarf has not yet been fully posited. In this paper we demonstrate that\nmass loss from a central star during post main sequence evolution can sweep\nplanetesimals into interior mean motion resonances with a single giant planet.\nThese planetesimals are slowly removed through chaotic excursions of\neccentricity that in time create radial orbits capable of tidally disrupting\nthe planetesimal. Numerical N-body simulations of the Solar System show that a\nsufficient number of planetesimals are perturbed to explain white dwarfs with\nboth dust and metal pollution, provided other white dwarfs have more massive\nrelic asteroid belts. Our scenario requires only one Jupiter-sized planet and a\nsufficient number of asteroids near its 2:1 interior mean motion resonance.\nFinally, we show that once a planetesimal is perturbed into a tidal crossing\norbit, it will become disrupted after the first pass of the white dwarf, where\na highly eccentric stream of debris forms the main reservoir for dust producing\ncollisions. These simulations, in concert with observations of white dwarfs,\nplace interesting limits on the frequency of planetary systems around main\nsequence stars, the frequency of planetesimal belts, and the probability that\ndust may obscure future terrestrial planet finding missions.\n