Ancient planetary systems are orbiting a large fraction of white dwarf stars

TL;DR

This study provides evidence that a significant fraction of white dwarfs host planetary systems, which survive stellar evolution, and shows that these systems can deliver substantial rocky material onto the white dwarf surface.

Contribution

It demonstrates that planetary systems around main sequence stars often survive into the white dwarf stage, with measurable accretion of planetary material.

Findings

Approximately 30% of white dwarfs show atmospheric pollution from planetary debris.

Polluted white dwarfs can accrete the mass of a large asteroid within 200 million years.

Detected element abundances suggest large, surviving planetary systems around white dwarfs.

Abstract

Infrared studies have revealed debris likely related to planet formation in orbit around ~30% of youthful, intermediate mass, main sequence stars. We present evidence, based on atmospheric pollution by various elements heavier than helium, that a comparable fraction of the white dwarf descendants of such main sequence stars are orbited by planetary systems. These systems have survived, at least in part, through all stages of stellar evolution that precede the white dwarf. During the time interval (~200 million years) that a typical polluted white dwarf in our sample has been cooling it has accreted from its planetary system the mass of one of the largest asteroids in our solar system (e.g., Vesta or Ceres). Usually, this accreted mass will be only a fraction of the total mass of rocky material that orbits these white dwarfs; for plausible planetary system configurations we estimate that this total mass is likely to be at least equal to that of the Sun's asteroid belt, and perhaps much larger. We report abundances of a suite of 8 elements detected in the little studied star G241-6 that we find to be among the most heavily polluted of all moderately bright white dwarfs.