Hubble sees Eye in the Sky

This Hubble image of planetary nebula Kohoutek 4-55 was taken by the Wide Field and Planetary Camera 2 on May 4, 2009. The colors represent the makeup of the various emission clouds in the nebula: red represents nitrogen, green represents hydrogen, and blue represents oxygen. K 4-55 is nearly 4,600 light-years away in the constellation Cygnus. Credit: NASA/ESA/JPL

Planetary nebulas have nothing to do with planets. They were named so because in early telescopes, they had the fuzzy look of planets in our outer solar system. In fact planetary nebulas sit throughout our galaxy. This one contains the outer layers of a red giant star that were expelled into space as the star entered its death throes.

Ultraviolet radiation from the remaining hot core of the star zaps the ejected gas shells, making them glow. A bright inner ring is surrounded by a bipolar structure. The entire system is then surrounded by a faint red halo, seen in the emission by lit-up nitrogen gas. This multi-shell structure is fairly uncommon in planetary nebulas, astronomers said.