From Earth’s perspective, one of the brightest stars in the sky
is the red supergiant Betelgeuse. Found in the constellation of
Orion, it’s large enough and close enough that when it’s destroyed
in an inevitable supernova, it will put on a spectacular light show
for anyone who happens to be on Earth to see it. So when the star
started dimming late last year, speculation rose that the show was
about to start.
Because Betelgeuse is so large and so close, it’s actually
possible to resolve some details of its surface rather than simply
seeing it as a point source of light. Some astronomers have used
the Very Large Telescope at the European Southern Observatory to do
just that, and they’ve found something extremely weird:
Betelgeuse’s dimming isn’t even.
As you can see in the before-and-after images above, Betelgeuse
was more or less spherical about a year ago. By December, it was
most decidedly not. While the upper hemisphere of the star looked
much as it had a year earlier, the lower portion looked diffuse and
distorted, with at least two regions of distinct brightnesses.
Source: FS – All – Science – News
New image shows Betelgeuse isn’t dimming evenly