Astronomers Spy Brightest Supernova Ever Seen

The “star stuff” that astronomer Carl Sagan famously said we are all made of was forged in the exploding supernovae of dying stars.

The phrase isn’t just a pithy remark for a bumper sticker, it’s backed up by science. "All the silver, nickel, and copper in the Earth and even in our bodies came from the explosive death throes of stars," said NASA scientist Steve Howell in a 2016 statement. "Life exists because of supernovae."

Now, researchers have announced the discovery of SN2016aps — the brightest, most energetic and probably the most massive supernova ever observed, reports Ryan Mandelbaum for Gizmodo.

Supernovae are huge explosions caused by the deaths of stars at least five-times the mass of our sun, according to NASA.

This particular supernova, first spotted in 2016, exploded with ten-times more energy than a typical supernova, the researchers report this week in the journal Nature Astronomy.

"The intense energy output of this supernova pointed to an incredibly massive star progenitor," says Edo Berger, astronomer at Harvard University and co-author of the research, in a statement. "At birth, this star was at least 100 times the mass of our Sun."

The extraordinary brightness, energy and other unique qualities of SN2016aps suggest to scientists that it could be the result of an extremely rare event known as a pulsational pair-instability supernova. These rare events occur when two massive stars merge before exploding.

The Panoramic Survey Telescope and Rapid Response System at Haleakala Observatory, Hawaii spotted the flash some 3.6 billion light-years from Earth on February 22, 2016. The phenomenon quickly drew attention from the scientific community and the team led by Berger collected observations and data from telescopes and sensors all over the world for more than two years to learn all they could about this massive stellar explosion.

Subsequent years of studying SN201aps helped explain the supernova’s exceptional brightness. Spectroscopic observations revealed that in the final years before the star’s violent demise, it shed a “massive shell of gas as it violently pulsated,” says Nicholl. “The collision of the explosion debris with this massive shell led to the incredible brightness of the supernova. It essentially added fuel to the fire."

But a follow-up study of SN201aps also produced a confounding observation: high levels of hydrogen gas. Stars this massive typically lose their hydrogen to stellar winds long before beginning to pulsate in the run-up to their supernovae. The preponderance of hydrogen, “prompted us to theorize that two less massive stars had merged together, since lower mass stars hold onto their hydrogen for longer,” says Berger. "The new star, borne of the merger, was heavy with hydrogen and also high enough in mass to trigger pair instability."

The discovery of such a bright, energetic supernova may help scientists discover others like it, especially as powerful new telescopes such as the James Webb Space Telescope and the Large Synoptic Survey Telescope come online, says Berger in a statement.

These more powerful telescopes will allow astronomers to peer deeper into space and glimpse the fading light of the universe’s early history, where supernovae are thought to be more common. Berger says we “will be able to see similar events so far away that we can look back in time to the deaths of the very first stars in the Universe.”

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