All the way back in 1181 AD, astronomers from Japan and China recorded seeing a bright, unusual pinpoint of light in the sky. Now, in a reprocessed image released in celebration of Chandra's 15th anniversary, the source of this light is revealed.
Called 3C58, you are looking at the aftermath of a supernova. At the heart of 3C58, there is a rapidly spinning pulsar — a neutron star, or the dense remnant of a once-massive star, with more exotic properties — encased by a ring of x-ray emission. This pulsar, in turn, has large jets of radiation emanating from its poles (pictured to the left and right), each extending several trillion miles across.
When high-energy particles from the jets meet the object's magnetic field, they create the complex loops surrounding the central star, which closely resemble the ones seen around the famous Crab Pulsar (the Crab Nebula's proteginer star). NASA notes that "the 3C58 pulsar, the Crab pulsar, and a growing list of other pulsars provide dramatic proof that strong electromagnetic fields around rapidly rotating neutron stars are powerful generators of both high-energy particles and magnetic fields."
SN 1181, the official name of the supernova remnant, is one of just a handful of supernovae ever bright enough to be seen by the naked eye, and it reportedly remained visible for 181 days before it faded from view. It must be said, however, that there is some controversy surrounding its official designation. An investigation that took place in 2013 revealed that it might be much older and more distant than previously predicted, therefore it might not be associated with SN 1181 after all.
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See a larger image here.