Vote for this video by social sharing!Betelgeuse stopped dimming in the middle of February, and now some of the first papers studying the anomalous brightness variation are starting to appear. It doesn’t look like the star got cooler, there wasn’t a giant starspot that lowered the output, and there wasn’t a cloud of gas in the way. Instead it seems like dust is likely to be the culprit.
We have some great images by the star using the SPHERE instrument at ESO, taken by Miguel Montargès showing a darker area on the star, this shows that the dimming wasn’t a global event.
There’s another image from December showing the dust environment further out from the star taken by Pierre Kervell using the VISIR instrument.
However the most interesting evidence is comes from a team who did spectroscopy, trying to figure out if the star had god cooler.
I want to cover this paper by Emily M. Levesque & Philip Massey
“Betelgeuse Just Isn’t That Cool: Effective Temperature Alone Cannot Explain the Recent Dimming of Betelgeuse” https://arxiv.org/abs/2002.10463
Because it offers a good explanation of how astronomers have to go about finding the temperature of stars and because Emily wrote an excellent Twitter thread explaining their process