Planet Debris Falling onto a White Dwarf

This video animation shows a burned-out star, called a white dwarf, accreting rocky debris left behind by the star's surviving planetary system. An asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. The asteroid is torn apart by the white dwarf's gravitational tidal forces and then impacts other debris on the ring, as seen by flashes of light.

Infalling asteroids pollute the dead star's atmosphere with silicon. This element is not found in white dwarfs, but it is part of a rocky planet's composition. This "planetary chemistry" implies that the white dwarf's progenitor star had planets composed of Earth-like material, and that such planets are common around stars. The telltale chemical fingerprints were identified by the Hubble Space Telescope's Cosmic Origins Spectrograph (COS). The dead star is one of two observed by Hubble in the Hyades star cluster, 150 light-years from Earth.