Supernova SN 1181 reveals rare ‘Zombie Star’ in Pa 30 Nebula

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 WM Keck Observatory have revealed unusual filaments extending from the core of this supernova remnant. The supernova, recorded as SN 1181, was observed near the constellation Cassiopeia 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 it had no visible celestial bodies associated with it. However, in 2021, scientists linked the 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 would normally have been destroyed. This partial explosion is classified as a Type Iax supernova. The team of researchers, led by Tim Cunningham and Ilaria Caiazzo, got a detailed picture 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 expanded at about 1,000 kilometers per second. They noted that this rate indicates that the material has not changed since the explosion in 1181.

New insights into Supernova

The research sheds light on the supernova’s asymmetry, indicating that the explosion’s characteristics were unusual. The findings raise further questions about the nature of supernovae and their remnants in the universe.