Astronomers have uncovered the mystery of Betelgeuse’s blackout thanks to detailed image analysis.
Recall that at the end of 2019, Betelgeuse, a bright orange star in the constellation Orion, faded by about 66%. Some scientists have speculated that this is a sign that the star is about to explode like a supernova. But by April 2020, Betelgeuse had regained its brightness.
To understand the reason for the unusual phenomenon, the authors compared images taken by the Very Large Telescope (VLT) in January and March 2020: they used their example to track the dynamics of changes in the surface of a star. They noted a noticeable darkening in the southern hemisphere, which had become ten times dimmer than usual. Moreover, the shape and intensity of the dark spot changed rapidly.
We saw how the star’s appearance changes in real time over several weeks.
Miguel Montarger, staff member of the Paris Observatory.
As a result, the authors concluded that the darkening was caused by a dust cloud: a few hours before the sharp decrease in brightness, the star ejected a large gas bubble.
This cooling was sufficient for heavier elements such as silicon to condense into solid dust in the gas cloud.