The global collaborative effort included Albert Zijlstra and Iain McDonald from The University of Manchester and involved astronomers from Germany, the US, Chile. It was led by Thavisha Dharmawardena of the Max Planck Institute for Astronomy.
Publishing their findings today in The Astrophysical Journal Letters the team confirm that the fading was not the result of dust particles but instead by the formation of star spots now covering up to two-thirds of Betelgeuse. The observed star spots have a temperature of 3500 Celsius, around 10% cooler than the rest of the star’s surface.
Professor Albert Zijlstra from The University of Manchester was an author of the new research findings. “For comparison, a typical sunspot is the size of the Earth. The Betelgeuse star spot would be a hundred times larger than the Sun. The sudden fading of Betelgeuse does not mean it is going supernova. It is a supergiant star growing a super-sized star spot.” said Prof Zijlstra.
The paper, Betelgeuse fainter in the sub-millimetre too: an analysis of JCMT and APEX monitoring during the recent optical minimum, by Thavisha E. Dharmawardena, et al. is published in The Astrophysical Journal Letters (2020)