Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 October 13
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Pelican Nebula Ionization Front
Credit: John Bally (U. Colorado) & Bo Reipurth (U. Hawaii), NOAO, AURA, NSF

Explanation: What's happening to the Pelican Nebula? The light from young energetic stars is slowly transforming the Pelican's cold gas to hot gas, with the advancing boundary between the two known as an ionization front. Most of these bright stars lie off the top of the image, but part of the bright ionization front crosses on the upper right. Particularly dense and intricate filaments of cold gas are visible along the front. Millions of years from now this nebula might no longer be known as the Pelican, as the balance and placement of stars and gas will leave something that appears completely different. The above image was taken with the Mayall 4-metre telescope at Kitt Peak National Observatory in Arizona, USA. The large circular artifact below the image centre is not real. The nebula, also known as IC 5070, spans about 30 light years and lies about 1800 light years away toward the constellation of Cygnus.

Tomorrow's picture: Rippling Iridescence

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