Tuesday, September 20, 2016
"A Look to the Heavens"
“What makes this cosmic eye look so red? Dust. The featured image from the robotic Spitzer Space Telescope shows infrared light from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation of the Water Carrier 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.
Click image for larger size.
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 have been generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud. Had the comet-like bodies formed in the distant planetary system, they would have survived even the dramatic late stages of the star's evolution.”