See here: https://en.wikipedia.org/wiki/Betelgeuse#Variability And from the orig...

		layer8 7 months ago \| parent \| context \| favorite \| on: Gemini North telescope discovers long-predicted st... See here: https://en.wikipedia.org/wiki/Betelgeuse#Variability And from the original NOIRLab link: “This discovery answers the longstanding mystery of the star’s varying brightness”.