Back in September 2014, astronomer Iair Arcavi at UC Santa Barbara discovered a new supernova in the night sky. While not particularly interesting, he did watch the star glow brightly, meaning it had exploded and was now dissipating.
Seeing as the best part was over, Arcavi had robotic telescopes at the Las Cumbres Observatory monitor it and then moved on to other studies. What happened next is one of the greatest space mysteries we’ve head in a while.
However, later in 2015, Arcavi asked a student under him to look through past telescope data and see if they had turned up anything interesting on the exploding stars he had been studying. Strangely, they uncovered that the ordinary supernova Arcavi had discovered was anything but. Instead of fading, it was growing brighter, as if ready to explode a second time.
Of course, this was the find of a lifetime for Arcavi. After all, stars obviously don’t explode more than once. So his team began observing the star every couple of days, and made an even bigger discovery over the next two years. Their data revealed the supernova grew bright for 600 days, instead of the 100 days of brightness of a regular supernova before it explodes. During that period, the weird star alternated between brightening and dimming five times. It was as if the star was exploding over and over without actually dying.
It’s the first incident of its kind that cosmologists have ever come across, and they have no idea how to explain it. The foremost theory they have so far is that, despite looking so much like a supernova, it’s actually just something that looks like it. Of course, they can’t be sure of even that, because they’re data doesn’t support it. All other evidence points to it being your average everyday exploding star.
In fact, there’s an even bigger plot twist. Diggin into archived telescope data, Arcavi and his found that the star has actually exploded before — over half a century ago. Data showed a supernova recorded in the same spot in the sky in 1954. So the question is, how does a star apparently explode at least four times in the course of 50 years?
Another theory that’s been gaining followers is that it’s an event called a pulsational pair-instability, or PPI. In stars 100 times the size of our Sun, they grow unstable when they reach the end of their life. At that point, the heat ignites oxygen in the star’s core, and it blows up and dissipates the outer layer of the body, giving us the impression the entire star is exploding. This goes on and on until the star eventually sheds all its matter and collapses into a black hole. Of course, no one has ever actually seen a PPI, so the discovery still holds plenty of weight, if it weren’t for the fact this also doesn’t exactly match the findings.
So basically, all scientists can say right now with full certainty is they have no idea why this immortal star just won’t die.
Source of news : Indiatimes