Dust and the Helix Nebula
Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image shows infrared radiation from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation Aquarius . The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula , representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models suggest the glow is produced by a dust debris disk . Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud . Formed in the distant planetary system, the comet-like bodies would have otherwise survived even the dramatic late stages of the star's evolution .