Image Credit: Jean-Christophe Lambry, ESA/Hubble & NASA
ESO 456-67 is a planetary nebula located some 10,000 light-years away from Earth in the constellation of Sagittarius (the Archer), in the southern sky. It is approaching us at approximately 93 kilometers per second.
Despite their name, planetary nebulae have nothing to do with planets. The name of planetary nebulae arose in the 18th century because of the visual similarity between some round planetary nebulae and the planets Uranus and Neptune when viewed through small optical telescopes. The name has stuck even though modern telescopes make it obvious that these objects are not planets at all.
Planetary nebulae represent the final brief stage in the life of a medium-sized star like our Sun. While consuming the last of the fuel in its core, the dying star (collapsing from a red giant to a white dwarf) expels a large portion of its outer envelope. This material then becomes heated by the radiation from the stellar remnant and radiates, producing glowing clouds of gas that can show complex structures, as the ejection of mass from the star is uneven in both time and direction.
Over the next several thousand years, ESO 456-67 will gradually disperse into space, and then the white dwarf will cool and fade away for billions of years. Our own Sun is expected to undergo a similar fate, but fortunately this will not occur until some 5 billion years from now.
In this image of ESO 456-67, it is possible to see the various layers of material expelled by the central star. Each appears in a different hue — red, orange, yellow, and green-tinted bands of gas are visible, with clear patches of space at the heart of the nebula.
It is not fully understood how planetary nebulae form such a wide variety of shapes and structures; some appear to be spherical, some elliptical, others shoot material in waves from their polar regions, some look like hourglasses or figures of eight, and others resemble large, messy stellar explosions — to name but a few.
This image is taken with the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope using three different color filters. A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Jean-Christophe Lambry.