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The star of the Supergiant Betelgeuse is smaller, closer than first thought

The star of the Supergiant Betelgeuse is smaller, closer than first thought

Credit: ALMA (ESO / NAOJ / NRAO) / E. O’Gorman / P. Kervella

It could be another 1

00,000 years until the giant red star Betelgeuse dies in a fiery explosion, according to a new study by an international team of researchers.

The study, led by Dr. Meridith Joyce from The Australian National University (ANU), not only gives Betelgeuse a new lease on life, but shows that it is both smaller and closer to Earth than previously thought.

Dr. Joyce that the supergiant – part of the constellation of Orion – has long fascinated scientists. But lately, it has behaved strangely.

“It’s usually one of the brightest stars in the sky, but we’ve observed two drops in Betelgeuse’s radiance since late 2019,” Drs. Joyce.

“This prompted speculation that was about to explode. But our study offers a different explanation.

“We know that the first dimming event is involved in a dust cloud. We found the second smaller event is probably due to star pulsations.”

Researchers have used hydrodynamic and seismic modeling to learn more about the physics that drive these pulses — and get a clearer idea of ​​what stage of its life Betelgeuse is.

According to fellow author Dr. Shing-Chi Leung from The University of Tokyo, the analysis “confirmed that the pressure gauges – which are important, sound waves – are the cause of the Betelgeuse bug.”

“Helium is burning in its core right now, which means it is nowhere near the explosion,” said Drs. Joyce.

“We can look around 100,000 years before an explosion occurs.”

Co-author Dr. László Molnár from the Konkoly Observatory in Budapest said the study also revealed how big Betelgeuse is, and how far it is from Earth.

“The actual size of the physical Betelgeuse has become a mystery – previous studies have suggested that it may be larger than the orbit of Jupiter. Our results suggest that the Betelgeuse only reaches two-thirds of it, which there is a radius of 750 times the radius of the sun, “said Dr. Molnár.

“When we had the physical size of the star, we determined the distance from Earth. Our results show that it was only 530 light years away from us – 25 percent closer than previously thought.”

The good news is that Betelgeuse is still very far from Earth for the eventual explosion to have a significant impact on it.

“It’s still a big deal when a supernova kills. And it’s our closest candidate. It gives us a rare opportunity to study what’s going on with stars like this before they explode,” Drs. Joyce.

The study was funded by The Kavli Institute for Physics and Mathematics of the Universe (WPI), The University of Tokyo, and facilitated by ANU Distinguished Visitor’s program. This includes researchers from the United States, Hungary, Hong Kong and the United Kingdom, as well as Australia and Japan.

The study was published in The Astrophysical Journal.

Betelgeuse continues to darken, dropping to 1.506 strength

Additional information:
Meridith Joyce et al. Standing on the Shoulders of the Giants: New Mass Estimation and Distance for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulation with MESA, The Astrophysical Journal (2020). DOI: 10.3847 / 1538-4357 / abb8db

Provided by The Australian National University

Citation: The star of Supergiant Betelgeuse is smaller, closer than first thought (2020, October 16) obtained on October 16, 2020 from https://phys.org/news/2020-10-supergiant-star -betelgeuse-smaller-closer.html

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