Super-Luminous Supernovae Powered by Magnetars: New Light Shed on Star Death

Supernovae are some of the brightest stars in the universe, exploding in a super-luminous display that our telescopes can pick up. Now, scientists have discovered what might be the source of power for these dying stars. It turns out that they may be fueled by magnetars--small and incredibly dense neutron stars with gigantic magnetic fields that spin hundreds of times per second.

"Supernovae are several billions of times brighter than the Sun, and in fact are so bright that amateur astronomers regularly search for new ones in nearby galaxies," said Matt Nicholl, one of the researchers, in a news release. "It has been known for decades that the heat and light from these supernovae come from powerful blast-waves and radioactive material. But recently some very unusual supernovae have been found, which are too bright to be explained in this way. They are hundreds of times brighter than those found over the last fifty years and the origin of their extreme properties is quite mysterious."

In order to learn more about supernovae, scientists examined two of them for more than a year. More specifically, they used Pan-STARRS, the Panoramic Survey Telescope and Rapid Response System. This telescope collected most of the data and allowed them to gather unprecedented details from the two supernovae.

During a supernova explosion, the star violently ejects its outer layers as its core collapses to form an extremely dense neutron star. This star weighs as much as the Sun but is only tens of kilometers across. In some cases, it's likely that the neutron star has a very strong magnetic field and spins incredibly quickly--about 300 times per second. As it slows down, it could potentially transmit this spin energy into the supernova via magnetism and make it brighter than normal. In fact, this is exactly what the scientists discovered with their recent data.

"These are really special supernovae. Because they are so bright, we can use them as torches in the very distant Universe," said Stephen Smartt, one of the researchers, in a news release. "By understanding the processes that result in these dazzling explosions, we can probe the Universe as it was shortly after its birth. Our goal is to find these supernovae in the early Universe, detecting some of the first stars ever to form and watch them produce the first chemical elements created in the Universe."

The findings are published in the journal Nature.