The mystery surrounding the dramatic dimming of red supergiant Betelgeuse, observed over a period of several weeks back in winter 2019, has finally been resolved. In astronomy circles this event is now known as Betelgeuse’s Great Dimming.
A paper published in Nature by a team based at the VLT (Very Large Telescope) has concluded that one part of Betelgeuse underwent a temporary convective cooling process on part of its photosphere, allowing a previously ejected cloud of stellar plasma to condense into a kind of opaque nebulosity, obscuring some of the light from the star over a period of time.
Enormous stars like Betelgeuse have highly turbulent and dynamic surfaces and this event has helped us better understand the periodic mass loss that red supergiants experience in their last stages of evolution, as they literally ‘puff away’ vast swathes of their extended atmosphere into space.
It’s fair to say we’re still at the very earliest stages of truly understanding the complex processes controlling these dying stars.
I feel very privileged and humbled to have witnessed this exciting event (with others) from the surface of a tiny world over 550 light years away, and by extension 550 years after it actually happened.
If you want a deeper dive I’ve included the nature paper link here.