Betelgeuse – a giant with blemishes https://www.mpg.de/15029676/0625-astr-053792-betelgeuse-a-giant-with-blemishes
Betelgeuse, the bright star in the constellation of Orion, has been fascinating astronomers in the recent months because of its unusually strong decline in brightness. Scientists have been discussing a number of scenarios trying to explain its behaviour. Now a team led by Thavisha Dharmawardena of the Max Planck Institute for Astronomy have shown that most likely unusually large star spots on the surface of Betelgeuse have caused the dimming.
“Towards the end of their lives, stars become red giants,” Dharmawardena explains