This nebula contains an enormous amount of sulphur, much higher than the average of other nebulae. Sulfur, and in particular hydrogen sulfide, are the elements responsible for the disgusting smell characteristic of eggs gone bad. If we imagined travelling to this nebula and being able to smell it, we would immediately recognise the unpleasant smell. For this reason this cosmic structure has been nicknamed the Rotten Egg Nebula.
The nebula was created by a dying star that is expelling its surface layers into space. From the image we can identify two substructures, yellow and blue.
The blue region is a bipolar outer shell consisting of high temperature but low density gas, within which the yellow structure is expanding. Here the gas is extremely dense, so much so that this region contains much of the initial mass of the star. In this region the gas is moving in two diametrically opposite directions at supersonic speeds (500 thousand km/h).
By studying the rate of expansion and the dynamics of the gases, astronomers have discovered that the main gas expelling that gave rise to the nebula occurred about 800 years ago. It is thought that in a thousand years the rotten egg nebula will have evolved into a planetary nebula.
Credit: NASA, ESA, Hubble.
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