Betelgeuse Illustration

Strange behavior Red Supergiant Betelgeuse smaller and closer than the first thought

Betelgeuse illustration. Credit: NASA, ESA and E. Wheatley (STScI)

It may be another 100,000 years before the giant red star Betelgeuse dies in a blaze, according to a new study by an international team of researchers.

The study, led by Dr. Meridith Joyce of The National University of Australia (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 says the transcendental – which is part of the constellation Orion – has long fascinated scientists. But lately, he’s been behaving strangely.

“It’s usually one of the brightest stars in the sky, but we’ve seen two drops in Betelgeuse brightness since late 2019,” said Dr Joyce.

“It simply came to our notice then. But our study offers a different explanation.

“We know that the first weakening incident involved a cloud of dust. We found that the second smallest event is probably due to the star’s pulses. “

The researchers were able to use hydrodynamic and seismic modeling to learn more about the physics that drive these pulses – and get a clearer idea of ​​what phase of Betelgeuse life is.

According to co-author Dr. Shing-Chi Leung from the University of Tokyo, the analysis “confirmed that the pressure waves – essentially the sound waves – were the cause of Betelgeuse pulse.”

“Right now the sun is burning at its core, which means it is not exploding anywhere,” said Dr Joyce.

“We could look about 100,000 years before an explosion.”

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

“Betelgeuse ‘s actual physical size was a bit of a mystery – previous studies have shown that it could be larger than its orbit Zeus. “Our results show that Betelgeuse extends to only two-thirds of that, 750 times the sun,” said Dr Molnár.

“Once we had the physical size of the star, we were able to determine the distance from Earth. Our results show that they are only 530 light-years away – 25 percent closer to what we previously thought. “

The good news is that Betelgeuse is still far from Earth for the potential explosion to have a significant impact here.

“It’s still a big deal when a supernova goes out. And this is our closest candidate. “It gives us a rare opportunity to study what happens to such stars before they explode,” said Dr Joyce.

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

The study was published in The Astrophysical Journal.

Reference: “Standing on the Shoulders of Giants: New Mass and Distance Estimations for Betelgeuse through Combined Evolutionary, Asteroseismic and Hydrodynamic Simulations with MESA” by Meridith Joyce, Shing-Chi Leung, László Molnár, Michael Ireland, Chiaki Kobayashi and Ken’ichi N , 13 October 2020, The Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / abb8db

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