The case of the zombie star


If you’re anything like us, you probably have limited knowledge of the solar system and stars, and how they work. We know they are balls of gas in the sky millions of miles away, and we know most of them die out over time, but that’s generally the extent of it. So, when we read the other day that a zombie star had been discovered, we thought it might have been a Walking Dead reference!

But no, this is actually a genuine star that has been discovered by scientists, and it’s fascinating. It seems as though every year we are making discoveries in space or about our solar system, and learning things we never knew before. This is one of the more recent discoveries and tells us that there are different types of stars out there from the ones we are used to. Let’s find out more:

How does it work with stars?

Well, stars are pretty amazing things, and often, by the time their light reaches us on Earth they will begin to start dying, which is kind of sad – but then they are thousands of light years away. Usually, the way it works with stars is that after millions and millions of years, the star begins to run out of hydrogen, and thus is unable to produce the nuclear fusion that causes its light. The core then collapses, causing a supernova which can last several months. The dead star usually then leaves behind a neutron star or black hole.

But what if it doesn’t die?

Sometimes, however, we get weird anomalies, such as a star remaining alive, which is not supposed to happen. So imagine everyone’s surprise when a recent discovery was made of a supernova from 2014 that continued to erupt for 600 days! The typical length of time this happens for is only around 100 days, so it was a surprise, to say the least. The longest a supernova explosion is ever expected to last is around 130 days, so this was unprecedented. And, things were about to get even more bizarre.

Going back further

This was enough of a surprise, but it was nothing compared with what scientists discovered upon further research. When looking it to it in more detail, they discovered evidence of another supernova in the exact same location, dating back to 1954. It was the same star! Incredibly, this star somehow was able to survive an explosion, only to then explode again 60 years later. Supernovas are meant to be a one-time deal, so this was very strange for the scientists who were studying and observing the star.

Game changer

After extensive research, it seems that this supernova has challenged all preconceived notions about how stars are supposed to work, and this could lead to many more discoveries. A new theoretical model was developed for stars, called pulsational-pair instability supernova. It forces astronomers to reexamine their calculations, and, though the supernova has begun dying in the last couple of years, it is still technically a star that is neither living nor dead – a zombie star!

Space can be a pretty amazing thing, and the universe throws up some staggering questions at times. This is a discovery likely to change the way we look at stars, and how we understand supernovas. We can’t wait to hear about further discoveries of zombie stars, and see how they come about.