Supergiant Star Betelgeuse Dimmed Mysteriously, and Now We Know Why

"We have directly witnessed the formation of so-called stardust."

The Great Dimming

In late 2019, astronomers noticed something strange: Betelgeuse, a red supergiant in the Orion constellation some 550 light years away from Earth (and the tenth brightest star in the night sky), abruptly dipped in brightness.

The strange event, now dubbed the "Great Dimming," had scientists scratching their heads — and leading some to believe it's about to blow up in a supernova.

But thanks to a team of scientists, who used the Very Large Telescope (VLT) in Chile, the dip isn't a sign of the star's imminent demise. It's most likely a gigantic dust cloud coming between us and Betelgeuse.

Making Stardust

In a new study published today in the reputable journal Nature, the international team laid out their theory. A dusty veil shaded the star, which caused the surface temperature of the supergiant to cool.

They suggest that prior to the Great Dimming, Betelgeuse let out a massive gas bubble that moved away from it. Thanks to a drop in surface temperature, the gas condensed into solid dust.

"We have directly witnessed the formation of so-called stardust," said Miguel Montargès, astronomer at the Observatoire de Paris in France, and team lead, in an official statement.

"The dust expelled from cool evolved stars, such as the ejection we've just witnessed, could go on to become the building blocks of terrestrial planets and life," said Emily Cannon, astrophysics PhD at KU Leuven in Belgium and co-author, in the statement.

In short, Betelgeuse isn't about to go AWOL — in fact, we haven't witnessed a supernova in our galaxy since at least the 17th century. In fact, it's quite the opposite: a nearby star breathing life into other planets around it.

Editor's note 6/17/2021: This story incorrectly stated the university KU Leuven is in the Netherlands. It is in fact located in Belgium.

READ MORE: Mystery of Betelgeuse's dip in brightness solved [ESO]

More on Betelgeuse: MIT Scientists: Nearby Star Appears to Be Cranking Out Dark Matter