Asteroid Will Cover Betelgeuse, May Reveal Its Visible Surface - Sky & Telescope - Sky & Telescope
▻https://skyandtelescope.org/astronomy-news/asteroid-will-cover-betelgeuse-may-reveal-its-visible-surface
Imagine your favorite constellation without one of its brightest stars. For a brief moment on December 12th, this may happen to Orion, at least for viewers in a narrow stretch from central Asia and southern Europe to Florida and Mexico. Around 1:17 UTC (8:17 p.m. EST December 11th), the main-belt asteroid 319 Leona will pass in front of Betelgeuse, the red star at Orion’s shoulder, and block its light for a few seconds.
An occultation of a 1st-magnitude star is rare — such an event is visible from Earth only every few decades — but watching one can give astronomers valuable scientific information. By precisely timing the duration of the occultation from many sites simultaneously, they can refine their knowledge of the size and shape of the asteroid. They may even be able to map Betelgeuse’s strangely large convective cells, by which the star brightens and darkens for months at a time. Betelgeuse is the 10th brightest star in our skies (+0.5 magnitude), so observers need only modest equipment to participate.