Quirks and Quarks

The 'super' in this supernova means the biggest and brightest one we've ever seen

Scientists observed SN2016aps in a galaxy 4.6 billion light-years from Earth.

Scientists observed SN2016aps in a galaxy 4.6 billion light-years from Earth

Artist's impression of the supernova. (Aaron M. Geller, Northwestern University IT)

A very rare supernova at least twice as bright and energetic as any other seen before has been identified in a galaxy 4.6 billion light-years from Earth.

Over a period of two years, Peter Blanchard, a postdoctoral researcher at Northwestern University's Center For Interdisciplinary Exploration and Research in Astrophysics (CIERA), and an international group of colleagues, were able to observe what became extremely rare supernova.  It turned out to be the first observation of a type whose existence had only been theorized. 

It is an example of an extremely rare "pulsational pair-instability" supernova, according to the team's study published in Nature Astronomy. This means that the stellar explosion, or supernova, was amplified as it merged with a shell of hydrogen gas that surrounded the star.

This gas had been "burped" away from the massive star prior to the explosion, said Blanchard.

Peter Blanchard inside a Magellan telescope in Las Campanas, Chile, one of many used to study SN2016aps. (Submitted by Peter Blanchard)

The explosion caught up with that layer of gas which made the resulting supernova both more energetic and brighter than any other seen before, according to Blanchard.

This supernova is also the result of the explosion of a much bigger star than any previously observed. Blanchard and his colleagues calculated the star's size to be between 50 to 100 solar masses. Typically supernovae are between eight and 15 solar masses. 

The astronomers are not quite sure what became of the core of this star after it exploded. The outcome depends on how much material remained at the core of the star after the explosion.  Below a critical mass, it would have collapsed into a neutron star, but if a little more material remained there might have been enough mass to form a new black hole.