Asteroid belt survival through stellar evolution: Dependence on the stellar mass

Abstract

Polluted white dwarfs are generally accreting terrestrial-like material that may originate from a debris belt like the asteroid belt in the Solar system. The fraction of white dwarfs that are polluted drops off significantly forwhite dwarfs with massesMWD ≥ 0.8·. This implies that asteroid belts and planetary systems around main-sequence (MS) starswith massMMS 3M may not form because of the intense radiation from the star. This is in agreement with current debris disc and exoplanet observations. The fraction of white dwarfs that show pollution also drops off significantly for low-mass white dwarfs (MWD 0.55M). However, the low-mass white dwarfs that do show pollution are not currently accreting but have accreted in the past. We suggest that asteroid belts around MS stars with masses MMS 2M are not likely to survive the stellar evolution process. The destruction likely occurs during the AGB phase and could be the result of interactions of the asteroids with the stellar wind, the high radiation, or, for the lowest mass stars that have an unusually close-in asteroid belt, scattering during the tidal orbital decay of the inner planetary system.