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Clown face/Eskimo Nebula (NGC 2392)
Jess Hendriksma

Clownface Nebula

When a star runs out of fuel (hydrogen), it begins to collapse on itself and in this process it ejects its outer layer in the surrounding space.  The stars core, known as a white dwarf,  is very dense and hot.  The high energy radiation emitted by the white dwarf excites the electrons in the ejected contents of the outer layers causing them to fluoresce.  This phenomena is known as a planetary nebula.  Despite the name, it has nothing to do with planets.  It was named by William Herschel who mistakenly identified the nebula as a planet due to its large, round shape.  Herschel is also credited with the discovery and naming of the clown face or Eskimo nebula.  This nebula was named for its resemblance to an Eskimos head inside a fur parka hood.  The Eskimo nebula is in the Milky way galaxy, near the constellation Gemini

This image shows the interesting shape of the Eskimo nebula.  The white dwarf star at the center glows bright and blue, indicating intense heat.  The gas clouds surrounding the white dwarf are green which indicate the presence of oxygen.  The cause of the strange shape of the clouds is not yet understood by astronomers.  In the image, two separate gas clouds are seen surrounding the white dwarf, making it a double shell planetary nebula.  This particular nebula is believed to be about 3,000 light years away from earth (Nemiroff).  The angular size of the nebula in the image is 50 arc seconds.  Using the small angle formula, the linear size of the Eskimo nebula was found to be 0.72 light years across. 

References:

Nemiroff, Robert. "The Eskimo Nebula from Hubble." Astronomy Picture of the Day. Ed. Jerry Bonnell. N.p., 3 May 2009. Web. 12 Apr. 2011. <http://apod.nasa.gov/apod/ap090503.html>.

Comins, Neil F., and William J. Kaufmann III. Discovering the Universe. 5th ed. New York: W.H. Freeman and Company, 2000. 304-05.

Guerrero, M A., Y H. Chu, R A. Gruendl, and M Meixner. "XMM-Newton Detection of hot gas in the Eskimo Nebula: Shocked stellar wind or collimated outflows?" Astronomy & Astrophysics 430.311 Feb. (2005): L69-72

Right Ascension (J2000) 07:29:12
Declination (J2000) +20:55:00
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, R, C (60s x 5)
Date observed March 24, 2011 11:51 PM, EST

 

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