Chemistry Reference and  Research
           
 
Periodic Table
- standard table
- large table
 
Chemical Elements
- by name
- by symbol
- by atomic number
 
Chemical Properties
 
Chemical Reactions
 
Organic Chemistry
 
Branches of Chemistry
Analytical chemistry
Biochemistry
Computational Chemistry
Electrochemistry
Environmental chemistry
Geochemistry
Inorganic chemistry
Materials science
Medicinal chemistry
Nuclear chemistry
Organic chemistry
Pharmacology
Physical chemistry
Polymer chemistry
Supramolecular Chemistry
Thermochemistry

Helix Nebula

NGC 7293, the Helix Nebula.
Enlarge
NGC 7293, the Helix Nebula.

The Helix Nebula (NGC 7293) is one of the closest planetary nebulae to Earth. It lies 140 parsecs or 450 light-years from Earth in the Aquarius constellation and has an angular diameter of about 0.5°.

Helix was discovered by Karl Ludwig Harding before 1824.

General information

The Helix Nebula is an example of a planetary nebula created at the end of the life of a Sun-like star. The outer gases of the star expelled into space appear from our vantage point as if we are looking down a helix. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic that it causes the previously expelled gas to fluoresce.

Helix lies about 650 light-years away towards the constellation of Aquarius and spans about 2.5 light-years. Recent pictures of Helix are a composite of newly released images from the ACS instrument on the Hubble Space Telescope and wide-angle images from the Mosaic Camera on the WIYN 0.9-m Telescope at Kitt Peak National Observatory.

Related topics

External links

01-04-2007 01:16:19
The contents of this article are licensed from Wikipedia.org under the GNU Free Documentation License. How to see transparent copy