Cat's Eye NebulaHqL-420 4/95
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About the Image
This image was taken by the Wide Field & Planetary Camera 2 on NASA's Hubble Space Telescope on September 18,1994. It is a combination os f three exposures totaling 30 minutes, using filters that show hydrogen, oxygen and nitrogen.
Cat's Eye NebulaThis colorful image reveals surprisingly intricate structure in the gas surrounding a dying star. The detail provides a "fossil record" of the different stages at the end of a star's life.
Planetary Nebula The term planetary nebula was coined by astronomers who first observed them using early telescopes: the nebula resembled the disks of planets such as Uranus and Neptune. Actually, a planetary nebula can be hundreds to thousands of times larger than our entire solar system and has nothing whatever to do with planets. A planetary nebula consists of shells of gas thrown off in successive outbursts by a normal star that is nearing the end of its life.
A Dying Star The dying star's most recent outburst produced an elongated shell of glowing gas. This gas is embedded in two gas clouds thrown off by the star in a previous outburst. Where these two clouds come together is marked by a clumpy ring of gas. What is left of the dying star is its dense helium core. The star, though dim, is still hot enough to illuminate the expanding gas shells which provide a record of the star's death throes. Our Sun will one day die a similar death: when it has burned up its hydrogen core, it will swell in size until it engulfs the Earth and cast off shells of gas that will continue to expand, turning into a planetary nebula.
DefinitionsHydrogen: a colorless, odorless gaseous element, the simplest, lightest and most abundant element in the universe - 93 of the total number of atoms and 76% of the weight of the universe's matter (atomic number 1, symbol H).
Helium: a colorless, odorless gaseous element; after hydrogen, the lightest gas and most abundant element in the universe (atomic number 2, symbol He).
Light Year: the distance light travels in a year (6 x 10^12 miles or 6 trillion miles).
Planetary Nebula: expanding clouds of gas thrown off by a dying star.
Fast FactsAge
The shells of gas were thrown off by the red giant star only 1,000 years ago.Location
The Nebula is in the northern hemisphere constellation Draco (the Dragon), near Ursa Major (the Great Bear, which contains the Big Dipper).Distance from Earth
3,000 light yearsSize
1/2 light year from end to end, about 400 times larger than our Solar System
Electronic AddressesYou can get images and other information about the Hubble Space Telescope using the Internet
Using ftp or gopher connect to ftp.stsci.edu and find files and directories in /pubinfo.
Using the World Wide Web (Mosaic, NetScape, Lynx, and other browsers), use URL http://www.stsci.edu/public.html and follow links from there.
