pa 30, located nearly 8,000 light-years from Earth, was discovered in NASA archives by Dana Patchick, an amateur astronomer and co-author of the article in 2013. Dana Patchick thought she had found a planetary nebula (her 30th discovery, hence the name Pa 30) but observing more , they were able to establish that it was in fact a supernova remnant. It is indeed a particular white dwarf, resulting from the collision of two stars.
The authors believe they have found the remains of SN1181, a supernova that appeared in northern Cassiopeia on August 6, 1181 and was reported by Chinese and Japanese observers for six months, astronomers call these fleeting, very bright apparitions “guest star“. Seen the measured expansion speed of the nebula, about 1100 kilometers per second, the nebula would be well 850 years old.
“I’ve never seen an object – and certainly no supernova remnant in the Milky Way galaxy – that looks like it, and neither have any of my colleagues.“, declares Robert Fesen in a press release from Dartmouth College. “Our deeper images show that [la nébuleuse] is not only beautiful, but now that we can see the true structure of the nebula, we can study its chemical composition and how the central star generated its remarkable appearance, then compare these properties to the predictions of models of rare white dwarf fusions“, concludes the astronomer.