Hubble Space Telescope Captures The Shrouds Of Dying Stars

The Hubble Space Telescope continues to capture stunning colorful snapshots of stellar burnout. New images reveal the beauty and complexity of planetary nebulae.

The image of NGC 7027, for example, is one of the first infrared views of planetary nebulae taken with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). In this image (shown here on the left), NICMOS peers through the dusty core of a young planetary nebulae to reveal the bright central star.

Other pictures taken by the Wide Field and Planetary Camera 2 catch the birth of planetary nebulae as they emerge from their cocoons of gas and dust.

This visible and infrared light picture of NGC 7027 provides a more complete view of how this planetary nebula is being shaped, revealing steps in its evolution. 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.

NICMOS has allowed astronomers to clearly see the transition layer from hot, glowing atomic gas to cold molecular gas. The origin of the newly seen filamentary structures is not yet understood. The transition region is clearly seen as the pink- and red-colored cool molecular hydrogen gas. An understanding of the atomic and chemical processes taking place in this transition region are of importance to other areas of astronomy as well including star formation regions.

WFPC2 is best used to study the hot, glowing gas, which is the bright, oval-shaped region surrounding the central star. With WFPC2 we also see material beyond this core with light from the central star that is reflecting off dust in the cold gas surrounding the nebula. Combining exposures from the two cameras allows astronomers to clearly see the way the nebula is being shaped by winds and radiation. This information will help astronomers understand the complexities of stellar evolution.

NGC 7027 is located about 3,000 light-years from the sun in the direction of the constellation Cygnus the Swan.

Editor's Note: For more Hubble photos and descriptions of the latest stellar findings, point your browser to:

http://oposite.stsci.edu/pubinfo/pr/1998/11/