One of the brightest stars in the night sky and the namesake for everyone’s favorite Michael Keaton movie (sorry “Batman” fans) has been acting strange for months now – getting larger, dimming, coming back even bigger – and NASA scientists believe they may have figured out why. Wouldn’t you know it – in this age of coronavirus, it appears Betelgeuse may have just sneezed?
“Observations by NASA's Hubble Space Telescope are showing that the unexpected dimming of the supergiant star Betelgeuse was most likely caused by an immense amount of hot material ejected into space, forming a dust cloud that blocked starlight coming from Betelgeuse's surface.
Hubble researchers suggest that the dust cloud formed when superhot plasma unleashed from an upwelling of a large convection cell on the star's surface passed through the hot atmosphere to the colder outer layers, where it cooled and formed dust grains. The resulting dust cloud blocked light from about a quarter of the star's surface, beginning in late 2019.”
(Where would astronomy be without the Hubble telescope?) NASA and astronomers worldwide have been watching Beletgeuse for some time because it has been growing (if it were placed in the center of our solar system, its outer edge would reach Jupiter) and appears to be heading towards supernova. That would be a thrill for astronomers – it’s only 725 light years away – but it would potentially create the closest black hole to Earth. And they’re not sure if or when this might happen. That’s why the dimming which began last year – referred to as the Great Fainting Event -- was a bit disconcerting. Fortunately, Hubble determined it was just a cosmic sneeze blowing enough thick plasma dust to hide a quarter of it from visibility.
As a follow-up, NASA aimed the STEREO (Solar and Terrestrial Relations Observatory) at Betelgeuse this summer. That’s when it started acting strange again.
“STEREO’s measurements revealed that Betelgeuse is dimming again — an unexpected development so soon after its last dim period. Betelgeuse typically goes through brightness cycles lasing about 420 days, with the previous minimum in February 2020, meaning this dimming is happening unexpectedly early.”
Is this something more than a stellar cold? Is Betelgeuse wearing a cosmic dust mask? Is it getting ready to blow – and we’re not talking about its stellar nose? Astronomers don’t know, so they‘re anxiously awaiting for fall 2020 when the dying star will be bright in the sky again (well, except for the dimness) and in a better position to be observed by more land and space telescopes.
Astronomers assure us that we’re too far away for Betelgeuse going supernova to affect us. Still, it would be a great sight to behold if it happens in our lifetime. Perhaps Beetlejuice/Michael Keaton can help. Say his name three times and then repeat one of his great lines from the movie:
“Go ahead, make my millennium.”