Scientists had previously estimated this to be the size of Betelgeuse compared to our solar system, but the new study revises that estimate downwards.
Betelgeuse is a red supergiant and it is awful compared to the size of our sun. But lately, it's been behaving strangely.
Speculations about the Betelgeuse explosion went into high gear as the star went through some weird dimming and brightening episodes from late 2019.
Scientists previously thought past year that Betelgeuse was on the verge of exploding as it became noticeably dimmer (at least, it was noticeable from an advanced telescope). But our study offers a different explanation.
New research suggests that the dimming events were actually due to a dust cloud obscuring the star from Earth and the star's natural pulsations, but also gives a timeframe for when it will go supernova.
The astronomers wanted to investigate Betelgeuse using physical models of how gas flows inside the star, and how seismic waves travel through it, because these depend on the internal structure of the star (a little like how seismic waves traveling through the Earth tell geologists about the structure inside our planet).
"It's burning helium in its core at the moment, which means it's nowhere near exploding", Dr. Joyce said.
"Our analysis confirmed that pressure waves - essentially, sound waves-were the cause of Betelgeuse's pulsation", said Dr. Shing-Chi Leung, an astronomer in the Walter Burke Institute for Theoretical Physics at Caltech.
"We could be looking at around 100,000 years before an explosion happens", she added.
"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".
Co-author Dr. László Molnár from the Konkoly Observatory in Budapest says the study also revealed how big Betelgeuse is, and its distance from Earth. Our results show that Betelgeuse only extends to 2/3 its radius, 750 times its radius.
Because Betelgeuse's size was better chosen, the team was able to calculate the distance from Earth more accurately and place it at a distance of about 530 light years, or about 25% closer than previously known.
The good news is Betelgeuse is still too far from Earth for the eventual explosion to have significant impact here.
"It's still really a big deal when a supernova bursts", Joyce said. And this is our closest candidate. It gives us a rare opportunity to examine what is happening Stars so before they explode, "said Dr. Joyce".
More information: Meridith Joyce et al. Standing on the shoulders of giants: New mass and distance estimates for Betelgeuse through combined evolutionary, asteroseismic and hydrodynamic simulations with MESA, The astrophysical journal (2020). The content is provided for informational purposes only.