A disintegrating minor planet transiting a white dwarf

Understand

White dwarfs are the end state of most stars, including the Sun, after they exhaust their nuclear fuel.

• Between 1/4 and 1/2 of white dwarfs have elements heavier than helium in their atmospheres, even though these elements should rapidly settle into the stellar interiors unless they are occasionally replenished.
• The abundance ratios of heavy elements in white dwarf atmospheres are similar to rocky bodies in the Solar system.
• This and the existence of warm dusty debris disks around about 4% of white dwarfs suggest that rocky debris from white dwarf progenitors' planetary systems occasionally pollute the stars' atmospheres.