The Jellyfish Nebula

The Jellyfish Nebula (IC443) at upper left is a supernova remnant in the constellation Gemini. It lies adjacent to the emission nebula Sharpless 249 at lower right. Image credit: Jeff Johnson at

The Jellyfish Nebula (IC443), upper left, is a supernova remnant in the constellation Gemini. It lies adjacent to the emission nebula Sharpless 249, a star forming region, at lower right in this image. Image credit: Jeff Johnson at

The Jellyfish Nebula, also called IC 443, is the sprawling remnant of a massive star that exploded as a supernova some 3,000 to 30,000 years ago in a gas-strewn patch of the Milky Way in the constellation Gemini. As you can see in the above image by Jeff Johnson, the shock wave from the explosion produced the particularly intricate lacework of nebulosity that makes up the Jellyfish. The nebula, which is about 5,000 light years away, is adjacent to a rich region of star formation called Sharpless 249.

Astronomers have identified the dense remains of the star that exploded to form the Jellyfish Nebula. It’s a neutron star, embedded towards one edge of the nebula, that radiates radio waves and X-rays as it spins rapidly and plows through a  cloud of interstellar gas at a speed of 800,000 km/h. The neutron star has a mass of about twice that of our Sun, but only spans the size of a small city. So a teaspoon-sized sample of the neutron star has the mass of a small mountain.

Only a few stars per century in the Milky Way will end their lives as supernovae like the star that formed the Jellyfish Nebula. But these exploding stars, along with smaller stars that eject their outer layers in a planetary nebula, make many of the chemical elements that are heavier than helium and nearly all the elements heavier than iron in the universe. The copper, mercury, gold, iodine and lead that we find on Earth were forged in these violent stellar deaths billions of years ago. Some of the heavy metals created in supernovae explosions, along with vast clouds of hydrogen and helium gas, will seed the formation of new stars and planets as a form of a galaxy-wide recycling of old stars into new stars. During this continuous cycle of star birth, death, and rebirth, new blisters of glowing gas light up the sky to call out the places where stars are born and where they will eventually come to an end.  

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