Astrophysicists at Southern Methodist University have discovered the explosion of a giant star 30 millions years ago that took place in a galaxy close to Earth. Prior to the supernova - which was equal to the detonation of 100 million suns - the star possessed a radius 200 times larger than the sun. The blast resulted in the release of material outward from the star at 10,000 kilometers a second.
The team's analysis examined the light curve and color spectrum of the exploding star, revealing new information on the existence and death of supernovae, which have puzzled scientists for years.
"There are so many characteristics we can derive from the early data," said Govinda Dhungana, an SMU physicist and lead author of the study. "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 explosion has been termed Supernova 2013ej and was one of the closest to the Earth in recent years, located in the spiral galaxy M74 in the constellation Pisces. Despite its proximity to the Earth compared to other explosions, it was still far enough away that light from the event took 30 million years to reach the Earth and be captured by telescopes in July 2013.
Dhungana and his team explored SN 2013ej using data from seven ground-based telescopes in combination with NASA's Swift satellite, capturing its temperature, mass, radius and chemical elements over a period of time from before the supernova's appearance in July all the way to more than 450 days after.
The team's findings will help in the understanding of supernovae, including whether they leave behind a black hole or neutron star.
"The core collapse and how it produces the explosion is particularly tricky," said Robert Kehoe, an SMU physics professor who leads the university's astrophysics team. "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. Using some of this information, we are also able to calculate the distance to this object. This allows us a new type of object with which to study the larger universe, and maybe someday dark energy."
The findings were published in the April 26 issue of The Astrophysical Journal.
