Monday will see a very rare night sky event when Betelgeuse—one of the most famous and brightest stars of all—is covered by an asteroid for about 12 seconds.
Although the event will be visible to the naked eye, it will only occur within a narrow path across Earth stretching from Asia to southern Europe, Florida, and eastern Mexico—though the Everglades National Park in Florida is in the path.
Due to be streamed live by The Virtual Telescope Network at 01:00 UTC on December 12 (20:00 EST on December 11), the occultation of Betelgeuse by asteroid 319 Leona will be a great chance for scientists to study the surface of the star and learn more about it.
Latest Details
The event will occur around 8:17 p.m. EST, according to Sky & Telescope, and the International Occultation Timing Association is where to head for the latest details.
Since it’s very small, it’s thought that 319 Leona will trigger a brief “ring of fire” annular eclipse as it passes across Betelgeuse, one of the biggest stars in the night sky.
Brightness of Betelgeuse
For those within the narrow path, there’s science to do. As 319 Leona passes in front of Betelgeuse and blocks its light, a very slight star shadow will fall across Earth’s surface. However, while the occultation of a star by an asteroid is typically a millisecond event, Betelgeuse is enormous—about 750 times the sun’s diameter.
So, over about 12 seconds, the asteroid will partially eclipse the star, cause a “ring of fire,” and then partially eclipse it before moving away. Astronomers using telescopes will see the brightness of Betelgeuse drop and then rise again.
Mapping A Supergiant Star
With some of its light blocked comes a scarce opportunity for astronomers with millisecond accuracy to map the shape and surface of Betelgeuse. That’s because its light will be relatively dim.
Betelgeuse changes shape slightly all the time. Its surface is a live issue because of dimming of another kind—Betelgeuse’s “great dimming” in late 2019 and early 2020, when it inexplicably lost about two-thirds of its brilliance. It left scientists perplexed about what was happening to Betelgeuse.
‘Great Dimming’ Of Betelgeuse
Betelgeuse was already known to be a variable star that waxed and waned in brightness over about 400 days and over six years, but nothing as dramatic as its “great dimming” had ever been observed. Since our sun ejects material into the solar system, so could Betelgeuse, but on a different scale. NASA’s Hubble Space Telescope appeared to confirm that a “burp” from within Betelguse produced a mass ejection of material that became a dust cloud above that caused the star to appear to dim as seen from Earth.
The Next Supernova
At about 550 light-years, Betelgeuse is the closest red supergiant star to the solar system. That’s why it’s so bright, but one day, it will become exceptionally bright. Now nearing the end of its life, Betelgeuse likely will explode as a supernova and be visible in the daytime sometime in the next 100,000 years.
That would be big news because a supernova hasn’t been seen in our galaxy since the 17th century, but it wouldn’t be dangerous—Betelgeuse is well beyond the 50 light-years “supernova danger zone.”
Wishing you clear skies and wide eyes.
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