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English: Resembling a rippling pool illuminated by underwater lights, the Egg Nebula (CRL 2688) offers astronomers a special look at the normally invisible dust shells swaddling an aging star. These dust layers, extending over one-tenth of a light-year from the star, have an onionskin structure that forms concentric rings around the star. A thicker dust belt, running almost vertically through the image, blocks off light from the central star. Twin beams of light radiate from the hidden star and illuminate the pitch-black dust, like a shining flashlight in a smoky room.

The artificial "Easter-Egg" colors in this image are used to dissect how the light reflects off the smoke-sized dust particles and then heads toward Earth.

Dust in our atmosphere reflects sunlight such that only light waves vibrating in a certain orientation get reflected toward us. This is also true for reflections off water or roadways. Polarizing sunglasses take advantage of this effect to block out all reflections, except those that align to the polarizing filter material. It's a bit like sliding a sheet of paper under a door. The paper must be parallel to the floor to pass under the door.

Hubble's Advanced Camera for Surveys has polarizing filters that accept light that vibrates at select angles. In this composite image, the light from one of the polarizing filters has been colored red and only admits light from about one-third of the nebula. Another polarizing filter accepts light reflected from a different swath of the nebula. This light is colored blue. Light from the final third of the nebula is from a third polarizing filter and is colored green. Some of the inner regions of the nebula appear whitish because the dust is thicker and the light is scattered many times in random directions before reaching us. (Likewise, polarizing sunglasses are less effective if the sky is very dusty).

By studying polarized light from the Egg Nebula, scientists can tell a lot about the physical properties of the material responsible for the scattering, as well as the precise location of the central (hidden) star. The fine dust is largely carbon, manufactured by nuclear fusion in the heart of the star and then ejected into space as the star sheds material. Such dust grains are essential ingredients for building dusty disks around future generations of young stars, and possibly in the formation of planets around those stars.

The Egg Nebula is located 3,000 light-years away in the constellation Cygnus. This image was taken with Hubble's Advanced Camera for Surveys in September and October 2002.
Data entre setembre de 2002 i octubre de 2002
date QS:P,+2002-00-00T00:00:00Z/9,P1319,+2002-09-00T00:00:00Z/10,P1326,+2002-10-00T00:00:00Z/10
Font https://hubblesite.org/contents/media/images/2003/09/1305-Image.html
Autor NASA and The Hubble Heritage Team (STScI/AURA); Acknowledgment: W. Sparks (STScI) and R. Sahai (JPL)

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Public domain
This file is in the public domain because it was created by NASA and ESA. NASA Hubble material (and ESA Hubble material prior to 2009) is copyright-free and may be freely used as in the public domain without fee, on the condition that only NASA, STScI, and/or ESA is credited as the source of the material. This license does not apply if ESA material created after 2008 or source material from other organizations is in use.

The material was created for NASA by Space Telescope Science Institute under Contract NAS5-26555, or for ESA by the Hubble European Space Agency Information Centre. Copyright statement at hubblesite.org or 2008 copyright statement at spacetelescope.org.

For material created by the European Space Agency on the spacetelescope.org site since 2009, use the {{ESA-Hubble}} tag.

Historial del fitxer

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Data/horaMiniaturaDimensionsUsuari/aComentari
actual01:18, 21 des 2006Miniatura per a la versió del 01:18, 21 des 20061.720 × 1.020 (148 Ko)Egghigh quality
00:06, 20 des 2006Miniatura per a la versió del 00:06, 20 des 2006800 × 474 (29 Ko)EggPlanetary nebula Egg * NGC 1705 * CRL 2688 {{PD-USGov}} Category:Planetary nebulae

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