On the Origin of Metals in Some Hot WhiteDwarf Photospheres

摘要

We have searched for evidence for dust and gas disks at a sample of hot DA white dwarfs 20000K < T_(eff) < 50000K, without success. Although their atmospheres arc polluted with heavy elements, we cannot yet convincingly and conclusively show that any of these objects is accreting metals from surrounding material derived from disrupted minor planets in an old solar system.