KEY POINTS

  • Bizarre dimming and brightening of Betelgeuse started in October 2019
  • Researchers used hydrodynamic and seismic modeling to study the physics surrounding supergiant star
  • Betelgeuse explosion will be significant in future studies on supernova events

Betelgeuse, the supergiant red star that has baffled astronomers since 2019, was found to be 25% closer to Earth and much smaller than previously thought. It was once known that Betelgeuse was bigger than Jupiter and 725 light-years away from Earth.

A new study published in The Astrophysical Journal found the celebrity star is only about 530 light-years from Earth, extends out to two-thirds of Jupiter, and has a radius 750 times that of the sun.

Betelgeuse caught the attention of astronomers when it dimmed and brightened in late 2019. The occurrence was unprecedented in that the dimming became visible even without the use of space telescopes. The visibility was peculiar given that estimates suggested that the dimming would have happened around the year 1,300.

The bizarre dimming and brightening of Betelgeuse started in October 2019, NASA reported in August. By mid-February, it dimmed again and lost more than two-thirds of its brightness. At that time, experts said Betelgeuse was showing signs that it would explode and could turn into a supernova in no time.

In the new study, a team of researchers used hydrodynamic and seismic modeling to study the physics surrounding Betelgeuse. They found that Betelgeuse’s first dimming was caused by a dust cloud while the second was the star’s own pulsations.

The team also found that Betelgeuse is not only smaller and closer than Earth but that it won’t explode anytime soon.

"It's burning helium in its core at the moment, which means it's nowhere near exploding," Dr. Meridith Joyce, lead author in the study and a researcher from The Australian National University (ANU), said in a press release.

"We could be looking at around 100,000 years before an explosion happens,” she added.

The researchers also clarified that people need not worry about the Betelgeuse explosion. It may be closer to Earth but it won't have a significant impact, they explained.

Nevertheless, the Betelgeuse explosion will be significant in future studies on supernova events.

"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," Dr. Joyce added.

Betelgeuse
Image: A graphic illustration of the event that caused Betelgeuse to dim. In the last panel, Betelgeuse is obscured by a giant dust cloud. NASA, ESA, and E. Wheatley (STScI)