A landmark study from the Australian National University (ANU) confirms Betelgeuse has tens of thousands of years before its supernova—and reveals it's smaller and closer than long assumed.
The red supergiant in Orion's shoulder is nearing life's end. Cosmically, its explosion looms "imminent," sparking keen interest when it dimmed sharply twice from January to March 2020.
Two leading theories emerged: an extreme variability episode in this pulsating star, or a massive gas and dust ejection from its intense stellar winds.
ANU researchers pinpointed the causes. "The first dimming involved a dust cloud, while the second, smaller event stemmed from the star's natural pulsations," says lead author and astrophysicist Meridith Joyce.
Hydrodynamic and seismic models further show Betelgeuse still fuses helium in its core. "Not for at least 100,000 years," Joyce assures.
The study also sizes Betelgeuse more precisely: smaller than expected.
"Betelgeuse's physical size has long puzzled us. Past estimates suggested it spanned beyond Jupiter's orbit," notes co-author László Molnár. "Ours show it reaches just two-thirds that far, with a radius of 750 times the Sun's."
Refined distance: 530 light-years away—25% closer than thought, per Dr. Molnár.
This proximity promises descendants a spectacular view. University of California, Santa Barbara models predict the blast's energy at ten billion times the Sun's, rivaling a quarter moon's brilliance for three months.
