In 1181 a rare explosion lit up the sky and we may finally have found what it left behind.

For 900 years, scholars and astronomers have sought to explain a bright cosmic object that briefly lit the skies over China and Japan in AD 1181. A new study may have finally solved the mystery.

The Pa 30 nebula – named Parker’s star, one of the hottest in the Milky Way – and the star it surrounds correspond to the phenomenon observed in the sky all those years ago, as measured by its modern position. , its speed of expansion, and state.

Observations show that the Pa 30 gas and dust cloud is spreading at a speed of 1,100 kilometers (684 miles) per second. This suggests that it originated from a central point around 1,000 years ago, most likely from a supernova explosion. This is perhaps what was observed by contemporary astronomers in 1181.

“Historical reports place the guest star between two Chinese constellations, Chuanshe and Huagai,” says astrophysicist Albert Zijlstra of the University of Manchester in the United Kingdom. “Parker’s Star fits the position well. It means the age and location matches the events of 1181.”

12th century astronomers reported an object in the sky as bright as Saturn that was visible for six months. They also recorded its position in the sky.

Astronomers have since used the observations to formulate a few hypotheses, but have not been able to confidently identify what he left behind – until now.

It is believed that Pa 30 and Parker’s Star were created by the fusion of two small, dense white dwarf stars, a rare event leaving behind what is known as an Iax-type supernova, or zombie star.

It is a rare category of supernova that scientists are learning even more about. What’s even rarer is having information on how the supernova started, as well as what remains are now being left behind.

“Only about 10 percent of supernovae are of this type, and they are not well understood,” says Zijlstra. “The fact that SN1181 was weak but faded very slowly fits this type. It is the only such event where we can study both the remaining nebula and the merged star and also have a description of it. ‘explosion itself. “

Since 1006 CE, there have only been five bright supernovae spotted in the Milky Way, and astronomers have already found matches for the other four. One of them, now known as the Crab Nebula in the constellation Taurus, is also believed to be around a thousand years old.

First discovered in 2013, it looks like Pa 30 now completes the set.

Previously, there had been some debate as to whether the merger of two white dwarf stars could result in a supernova like this. The discovery therefore has a lot to teach astronomers about other similar supernovas.

“It is the only Iax-type supernova where detailed studies of the remaining star and nebula are possible,” Zijlstra explains. “It’s nice to be able to solve both a historical mystery and an astronomical mystery.”

The research was published in the Letters from astrophysical journals.