English: The Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has captured a glimpse of a brief stage in the burnout of NGC 7027, a medium-mass star like our sun. The infrared image (on the left) shows a young planetary nebula in a state of rapid transition. This image alone reveals important new information. When astronomers combine this photo with an earlier image taken in visible light, they have a more complete picture of the final stages of star life.
NGC 7027 is going through spectacular death throes as it evolves into what astronomers call a "planetary nebula." The term planetary nebula came about not because of any real association with planets, but because in early telescopes these objects resembled the disks of planets.
This image is composed of three exposures, one from the Wide Field and Planetary Camera 2 (WFPC2) and two from NICMOS. The blue represents the WFPC2 image; the green and red, NICMOS exposures. The white is emission from the hot gas surrounding the central star; the red and pink represent emission from cool molecular hydrogen gas. In effect, the colors represent the three layers in the material ejected by the dying star. Each layer depicts a change in temperature, beginning with a hot, bright central region, continuing with a thin boundary zone where molecular hydrogen gas is glowing and being destroyed, and ending with a cool, blue outer region of molecular gas and dust.