https://www.cnet.com/news/mysterious-gr ... explained/
Extract:
(c/net) Before COVID-19 exploded and dominated global headlines, the possibility of nearby giant star Betelgeuse literally exploding captured its own share of attention. Betelgeuse went through a historically sudden and drastic period of dimming over several months in late 2019 and early 2020, leading some to wonder if the gigantic star might be preparing to go supernova. New research suggests it would be premature to write an obituary for the red supergiant.
During the so-called Great Dimming of Betelgeuse, the star was 10 times darker than usual, Miguel Montargès from the Observatoire de Paris, France and colleagues report in a paper published in the latest issue of the journal Nature.
….Red supergiants are the largest stars in the universe, representing a stage in the evolution of giant stars in which they expand outward, begin to cool and lose mass as they progress toward going out with a big blast in the end.
The observations of Betelgeuse seem to show the Great Dimming was actually caused by just such a mass loss incident. The star expelled a clump of gas near a region on the southern portion of its surface that developed a cold patch shortly thereafter. This cooling of the ejected gas allowed it to condense into literal stardust.
"This process generated a dense southern dust cloud that temporarily blocked much of Betelgeuse's light, giving us what we saw as the Great Dimming," explained University of Washington astronomer Emily M. Levesque, who was not a part of the research team, in a companion commentary published in Nature.
