Newly Discovered Supernovas Preceded by Stellar Explosion

Stars have a tendency of going supernova. Yet before they do, there are some warning signs. Stars will undergo a type of "mini-explosion", which is when they throw a good-sized chunk of their material off into space. While several models predicted this behavior, actual observations of this outburst had yet to be made. Yet now, researchers have found an example of this phenomenon--the essential explosion before the storm.

The findings, published in Nature, examined a pre-supernova event that took place. Eran Ofek of the Weizmann Institute and his team searched the skies for supernova events using telescopes at the Palomar Observatory in California. They wanted to observe exactly what happens before one of these massive explosions. Eventually, they found the perfect example. The researchers encountered a star that ejected a mass of material before it went supernova a month later.

In order to calculate the possibility of this happening without it being related to going supernova, the researchers made a statistical analysis. They found, though, that there was only a .1 percent chance that the outburst and supernova event were unrelated occurrences.

The star that the researchers studied was massive--at least eight times the mass of our own sun. As it aged, the internal nuclear fusion that kept it going produced heavier and heavier elements. Eventually, the star's core was mostly made of iron, causing the star to collapse inward as it exploded.

So what was the cause of the pre-explosion outburst? Ofek hypothesizes that it was due to the star's core. The material was ejected straight from the core through the star's surface by gravity waves. The team believes that continued research will show that this type of mini-explosion will almost always precede this type of supernova, known as a type IIn supernova.

Exactly why this mini-explosion occurs is still up for debate. However, this research could pave the way for predicting supernovas in the future.