A supernova that appeared in 1181 has been linked to the Pa 30 nebula giving us a rare “zombie star.” This discovery raises new questions about how these celestial events unfold. Advanced imaging techniques from the W.M. Keck Observatory uncovered unusual filaments expanding from the core of this supernova remnant. The supernova, recorded as SN 1181, was observed near the Cassiopeia constellation and shone for six months before fading. It is one of the few pre-telescope supernovae documented in history.
For centuries, SN 1181 was considered an “orphan” because no visible celestial bodies were connected to it. However, in 2021, scientists linked its remnant to the Pa 30 nebula, which was first discovered in 2013 through citizen science efforts.
The Zombie Star
At the heart of the Pa 30 nebula is the “zombie star,” a remnant of the original explosion. This star survived a thermonuclear explosion on a white dwarf, which typically would have been destroyed. This partial explosion is classified as a Type Iax supernova. The team of researchers, led by Tim Cunningham and Ilaria Caiazzo, obtained a detailed view of the strange filaments that resemble dandelion petals.
Advanced Imaging Techniques
Using the Keck Cosmic Web Imager (KCWI), scientists first created a 3D map of the nebula. This technology allowed them to measure the speed of the filaments, which are expanding at about 1,000 kilometers per second. They noted that this speed indicates the material has not changed since the explosion in 1181.
New Insights into Supernova
The research sheds light on the asymmetry of the supernova, indicating that the explosion’s characteristics were unusual. The findings prompt further questions about the nature of supernovae and their remnants in the universe.