"helium white dwarfs" . "and shortly thereafter a white dwarf" . "white dwarfs" . "carbon-oxygen white dwarf" . . "White dwarf" . "white-dwarf" . . "D" . "white dwarfs to cool" . "metal lines" . "White Dwarf" . . "white dwarf stars" . "ONeMg white dwarf" . . "white or degenerate dwarf" . "DA2" . . "strongly-magnetized white dwarfs" . "polluted" . . "white dwarf star" . . . . "to cool to this temperature" . "white" . "DZ7" . . . . "white dwarf pollution" . "DC5" . . . "White dwarf" . "massive white dwarf" . . "DA4" . . "Sun as White dwarf" . "DQ6" . . . . "rocky debris accretion episode" . "DA white dwarf" . "DXP9" . . "White dwarf#Debris disks and planets" . . . . . "white dwarf" . . "stellar phenomenon" . "WD" . "DB" . "spectral type" . "DQ" . "White dwarf#Stars with very low mass" . . . "White dwarf#Atmosphere and spectra" . . . "accreted rocky debris" . . "helium white dwarf" . "central star" . "DQZ" .