For nearly six months during the year 1181, people looked up to the skies to find a new star glittering in the constellation Cassiopeia. Chinese and Japanese astronomers recorded the rare event, an explosion of a star, or supernova. In the centuries since, astronomers have searched for the remains of the blast, but it was not until 2013 that they were finally found. As part of a citizen scientist project, amateur astronomer Dana Patchick-who had sifted through images taken by the now-retired Wide-field Infrared Survey Explorer , or WISE-found a nebula at the site where the supernova had occurred.
Further observations convinced astronomers that this nebula, called Pa 30, was in fact the leftover ejected material from the 1181 supernova. Later, in 2023, astronomers discovered strange filaments within the supernova remnant, which resemble the wispy tendrils of a dandelion flower.
Now, with the help of the Caltech-built Keck Cosmic Web Imager (KCWI) at the W. M. Keck Observatory in Hawai'i, astronomers have, for the first time, mapped the location of those unusual filaments in three dimensions in addition to the speed at which they are streaming outward from the site of the blast.
"A standard image of the supernova remnant would be like a static photo of a fireworks display," says Caltech professor of physics Christopher Martin , who led the team that built KCWI. "KCWI gives us something more like a 'movie' since we can measure the motion of the explosion's embers as they streak outward from the central explosion."
