Artist's Impression of a White Dwarf 'Polluted' with Planet Debris
This is an artist's impression of a burned-out star, called a white dwarf, accreting rocky debris left behind by the star's surviving planetary system. At lower right, an asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. Infalling asteroids pollute the white dwarf'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.