Betelgeuse. Betelgeuse. Betelgeuse.
ALMA (ESO/NAOJ/NRAO)/E. O'Gorman/P. KervellaIf you're experiencing the creepy sensation of someone breathing down your neck, it might be Betelgeuse. The infamous star -- subject of an exciting will-it-or-won't-it supernova discussion earlier this year -- may be much closer to Earth than we suspected.
Betelgeuse is a red supergiant and it's monstrous compared with the size of our sun. A study published in The Astrophysical Journal this week unveils some new calculations of the star's mass and distance, and gives us an estimate for when it's likely to go supernova.
The speculation around Betelgeuse exploding kicked into high gear when the star went through some odd dimming and brightening episodes starting in late 2019. Scientists believe a dust cloud caused one of these events. "We found the second smaller event was likely due to the pulsations of the star," said lead author Meridith Joyce, in a statement from The Australian National University (ANU) on Friday.
The science team used modeling to sort out what was going with the pulsations, tracing it to what co-author Shing-Chi Leung of the University of Tokyo described as "pressure waves -- essentially, sound waves." This activity helped the researchers figure out where the star is in its life cycle.
Scientists had previously estimated this as the size of Betelgeuse compared with our solar system, but the new study revises that estimate down.
ESOThe upshot is that Betelgeuse isn't in danger of going supernova anytime soon. It could easily take 100,000 years before it gets to that stage. This is in line with what other scientists have suggested.
The study also shakes up our knowledge of the star's size. "The actual physical size of Betelgeuse has been a bit of a mystery -- earlier studies suggested it could be bigger than the orbit of Jupiter. Our results say Betelgeuse only extends out to two thirds of that, with a radius 750 times the radius of the sun," said co-author Laszlo Molnar of the Konkoly Observatory in Budapest.
With Betelgeuse's size dialed in better, the team was able to make a more accurate calculation of its distance from Earth, placing it at around 530 light-years away, or about 25% closer than previously known. That's still plenty far enough that Earth won't be harmed by Betelgeuse's future explosion.
"It's still a really big deal when a supernova goes off. And this is our closest candidate. It gives us a rare opportunity to study what happens to stars like this before they explode," Joyce said.
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October 18, 2020 at 01:46AM
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Celebrity star Betelgeuse is smaller and closer to us than we thought - CNET
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