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Detailed Images of a Distant Star Hold Clues to Its Ultimate Fate

Sitting some 640 light years from our planet, the star Betelgeuse is on the verge of supernova

Behold, ALMA's image of Betelgeuse (ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella)
smithsonian.com

You’ve probably seen Betelgeuse, even if you don’t know it. No, we’re not talking about the 1988 movie starring Michael Keaton. Betelgeuse is a star—the second brightest star in the constellation Orion, one of the most recognizable star groups in the night sky. Now, new images from the European Southern Observatory are giving us even better glimpses of this flaming ball of gas, reports Ryan F. Mandelbaum at Gizmodo, taken with the highest resolution yet for any star besides our own sun.

Betelgeuse is interesting for several reason. First, it's relatively close at roughly 640 light years away. It’s also big, clocking in at around 1,400 times the radius of our own sun. And it’s volatile. The eight-million-year-old red giant is on the brink of star death, also known as going supernova. When this happens the glowing ball will explode in a flash so bright it will likely be visible on Earth—even during daylight hours. 

As Ethan Siegal at Forbes reports, Betelgeuse could blow up at any time. It could explode right now—but it would take 640 years for the light of that explosion to reach our planet. And there is still much to learn about the big event before that happens. Scientists are particularly interested in the reason behind the lumpy, uneven surface of the star, which could hold clues to the timing and products of this explosion.

So a team of scientists trained the Atacama Large Millimeter/submillimeter Array on the star, capturing impressive details of Betelgeuse in infrared, ultraviolet and visible wavelengths. They published their results in the journal Astronomy & Astrophysics.

“We have known for decades that the visible surface of Betelgeuse is not uniform, but ALMA has now shown us in detail that the temperature in its inner atmosphere is also not uniform,” lead author Eamon O'Gorman, astronomer at the Dublin Institute for Advanced Studies, tells Gareth Morgan at Independent.ie. These lumps and bumps on the surface of the star could be due to convection processes in its interior, like boiling water, Mandelbaum reports. And as the star convects, it loses gas and dust to space. 

Researchers were particularly interested in the rate of this loss. After burning through all of its nuclear fuel, the extreme gravity of the star’s core will contract its mass, eventually causing an enormous explosion, generating a ton of energy along with heavy elements. But the exact elements formed are partly determined by how quickly the star looses its gas and dust before it goes supernova.

It is this same process that created the first elements on our own planet. “We want to understand how the process [of element production] works in stars that are long gone since it’s those stars that let us know how the elements we’re made of were made,” co-author Iain McDonald from the University of Manchester tells Mandelbaum. “If you blow it up soon you might end up with iron and nickel and gold, silver. But if you blow it up later you might make some of the other stuff like lead, barium, carbon or oxygen.”

When it does happen, the explosion will be pretty spectacular. But don't worry: No significant amount of that cosmic radiation will reach us. It just will make a pretty space picture.

About Jason Daley

Jason Daley is a Madison, Wisconsin-based writer specializing in natural history, science, travel, and the environment. His work has appeared in Discover, Popular Science, Outside, Men’s Journal, and other magazines.

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