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Future Supernova

August 2, 2018

A brilliant star in the southern constellation Carina may be about to meet its doom. In fact, it may have done so already, but it’s so far away that its light hasn’t had time to reach us. But when it does, it’ll be quite a show.

The star is known as SBW1. It was discovered about a decade ago. It’s a blue supergiant. It’s probably about 20 times as massive as the Sun, many times wider, and tens of thousands of times brighter. Such a star is fated to explode as a supernova. That blasts its outer layers into space, and briefly makes the star shine as brightly as billions of normal stars.

One indication that such a blast is imminent is a ring of gas and dust around the star. It’s built like a string of beads, with not much between the beads. The material was ejected from the star’s equator, then formed the bead structure as it expanded and cooled.

A similar ring encircled the brightest supernova seen from Earth in the last few centuries — Supernova 1987A, in a companion galaxy to the Milky Way. The star itself was a near twin to SBW1.

Astronomers didn’t see the ring around 1987A until after the star blew itself to bits. But studies suggest that it was expelled about 10,000 years before the star exploded. And that suggests that SBW1 could be about to explode as well. In fact, since the star is more than 20,000 light-years from Earth, it could have exploded already, and the light from the blast is racing toward us even now.

Script by Damond Benningfield

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