NASA Astronomy Picture of the Day Collection

Dust and the Helix Nebula

Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image [ http://www.spitzer.…ssc2007-03/index.sht ml ] shows infrared [ http://coolcosmos.ip ac.caltech.edu// ] radiation from the well-studied Helix Nebula [ http://antwrp.gsfc.…] (NGC 7293) a mere 700 light-years away in the constellation Aquarius [ http://www.seds.org…]. 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 [ http://www.noao.edu…], 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 [ http://arxiv.org/ab…] suggest the glow is produced by a dust debris disk [ http://antwrp.gsfc.…]. 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 [ http://www.ifa.hawa…] or cometary Oort cloud [ http://www.windows.…link=/comets/Oort_cl oud.html&edu=high ]. Formed in the distant planetary system, the comet-like bodies have otherwise survived even the dramatic late stages of the star's evolution [ http://en.wikipedia…].

NASA [ http://www.nasa.gov…], JPL-Caltech [ http://ssc.spitzer.…], Kate Su (Steward Obs [ http://ssc.spitzer.…], U. Arizona) et al. [ http://arxiv.org/ab…]

Arizona

Hawaii

Goddard Space Flight Center (GSFC)

Jet Propulsion Laboratory (JPL)

Stennis Space Center (SSC)

Sun

COMETS

Aquarius

Spitzer Space Telescope

nebula

http://antwrp.gsfc.…

SPD-APOD-ap070223