Betelgeuse: Nearby 'supernova' star's dimming explained

Astronomers say big cool patches on a "supergiant" star close to Earth were behind its surprise dimming last year. Red giant stars like Betelgeuse frequently undergo changes in brightness, but the drop to 40% of its normal value between October 2019 and April 2020 surprised astronomers.

betelgeusecosmologysupernova
LINK