In a faraway galaxy, astronomers have spotted a spectacular stellar explosion that dwarfs the average supernova.
The object in question is Supernova 2013ej, which is located in the galaxy M74, 30 million light-years from us. It exploded with an energy equivalent to the detonation of 100 million Suns and it blasted out material at 10,000 kilometers (6,200 miles) per second. The progenitor star is supposed to be about 250 times as wide as our Sun and 15 times as heavy.
In a new paper, published in the Astrophysical Journal, researchers were able to study this fascinating object from the very beginning and for more than 450 days after, which allowed them to gain incredible insight into how this phenomenon evolved over time.
“There are so many characteristics we can derive from the early data,” lead author Govinda Dhungana from the Southern Methodist University in Dallas said in a statement. “This was a big massive star, burning tremendous fuel. When it finally reached a point its core couldn’t support the gravitational pull inward, suddenly it collapsed and then exploded.”
The star that generated SN 2013ej was a complex object. After stars run out of hydrogen in their core, they progressively burn heavier and heavier elements until the weight of the star itself is not balanced anymore and collapses in on itself. The gravitational collapse of the core is quick and powerful enough to fuse elements together, releasing so much energy that the star blows apart.
“The core collapse and how it produces the explosion is particularly tricky,” said Robert Kehoe, co-author of the study. “Part of what makes SN 2013ej so interesting is that astronomers are able to compare a variety of models to better understand what is happening.”
Being able to have a correct predictive model of these objects allows astronomers to know their true luminosity. By comparing how bright they appear in the sky, scientists are able to measure how far away they are. Having supernovae as “standard candles” permits scientists to understand how quickly the universe is expanding.
The researchers also looked at the light spectrum and were able to work out what kind of elements were produced by this object. This is particularly important because supernovae are responsible for enriching the interstellar medium with heavy elements like oxygen, calcium, iron, and so on.
“Supernovae have death and birth written all over them,” Kehoe said. “Not only do they create the elements we are made of, but the shockwave that goes out from the explosion – that’s where our Solar System comes from.”
2
