Super-bright rare supernovae explained

Credit: UCSB

A few years ago, scientists discovered two supernovae that were brighter and farther away than any we’ve ever seen before. Because of their extreme brightness and distance, their existence first baffled astronomers. In theory, based on what we know about how supernovae form, they should not appear so bright, especially from so far away. However, scientists at the University of California in Santa Barbara determined that these two rarities exist due to something called a magnetar.

During a supernova, a massive star collapses into a black hole or normal neutron star. Although they do emit light, thanks to radiation generated during the event, most of these collapsed stars don’t shine with as much luminosity as these two do, even though the “little” ones are still impressive. However, the UCSB scientists believe magnetars are why we can see these super-bright supernovae from so far away. Magnetars are neutron stars with magnetic fields that are trillions of times more than what exists on Earth. They are small and compact, but their mass is almost equal to that of the Sun. They spin incredibly fast and create an energy that would create much more luminosity than typically seen in supernovae.

The scientists used models to test their theory. They believe that each star became small after exploding, but that it began to spin rapidly, creating a magnetar. The energy created from that “unleashed a magnetic fury.” That energy is powerful enough to emit ultraviolet light that shifted its wavelength so that it was seen by telescopes on Earth, over 10 billion light years away. This is the first time we’ve ever observed anything like this. The research team believes these two stars exploded a long time ago, before our Sun even existed.

So how rare is this occurrence, which scientists refer to as super luminous supernovae? For every supernova, only one in every 10,000 explode this way. Scientists believe that they were more common when the universe was much younger, but today, not so much.

Via University of California, Santa Barbara

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