Distant star explosion is brightest ever seen, study finds

Distant star explosion is brightest ever seen, study finds

April 18, 2020 1 By tecnb

This supernova is one for the record books.

A mammoth star explosion known as SN2016aps, which occurred in a galaxy about 3.6 billion light-years from Earth, is the brightest supernova ever seen, a new study reports.

“We can measure supernovae using two scales: the total energy of the explosion, and the amount of that energy that is emitted as observable light, or radiation,” study lead author Matt Nicholl, a lecturer in the School of Physics and Astronomy and the Institute of Gravitational Wave Astronomy at the University of Birmingham in England, said in a statement.

“In a typical supernova, the radiation is less than 1 percent of the total energy,” Nicholl added. “But in SN2016aps, we found the radiation was five times the explosion energy of a normal-sized supernova. This is the most light we have ever seen emitted by a supernova.”

SN2016aps is so odd and so extreme that Nicholl and his colleagues think it may be a “pulsational pair-instability” supernova, in which two big stars merge before the whole system goes boom. Such events are hypothesized, but astronomers have never confirmed their existence observationally.

As its name indicates, SN2016aps was discovered in 2016, by the Panoramic Survey Telescope and Rapid Response System in Hawaii. Nicholl and his team tracked the event for two years with NASA’s Hubble Space Telescope and a variety of instruments on the ground, watching as the supernova’s brightness faded to just 1% of its peak output.

These observations allowed the researchers to characterize the explosion and piece together how it may have happened. For example, the team determined that much of SN2016aps’ brightness probably derived from the interaction between the supernova and a surrounding shell of gas. Before they explode, doomed giant stars experience violent pulsations, which eject such shells into space.