Betelgeuse lowered its temperature by 170 degrees during its dimming

18. 08. 2021

New study argues, that dimming of Betelgeuse between october 2019 and march 2020 was caused by a huge dark spot on surface of the star. The spot caused a temperature drop by at least 170 K, which caused the stars dimming. Previous studies showed, that lower brightness of the star could also be explained by cloud of dust covering part of the star.

Betelgeuse

Theory 1: dust cloud
One of the theories that try to explaing dimming of the Betelgeuse star is a dust cloud, that covered part of the star. The material came from the star itself, after cooling it created a dust (or a gas) cloud.

Theory 2: spot on the surface
Another theory is a dark spot on the surface of Betelgeuse. This region with lower temperature and brightness would cause apparent dimming of the star. This theory is also supported by submilimeter observations.

Theory 3: cycles combination
The dimming of Betelgeuse could be also explained by a rare combination of star cycles and their unusual strength. In this case it would be a concurrence between 5.9 year cycle and 425 days period.

Theory 4: iminent supernova
And then there is the supernova. Betelgeuse is at the end of its main sequence life and its mass is big enough to cause a supernova explosion. No one really knows what exactly happens before a star goes supernova, and a dimming might be one of processes that come before it. However scientists are pretty confident, that Betelgeuse has about 100 thousand years more before that happens.