The mystery of

Astronomers have finally solved the mystery behind the “Great Dimming of Betelgeuse” – a star in the Orion constellation that started dimming in late 2019 and returned to its original brightness by 2020. In a new study, astronomers concluded that the reason behind stars’ dimming was the combination of a big dust cloud and a drop in temperature which blocked the light of the young star.

Betelgeuse, a red supergiant and one of the brightest orange stars in the Orion constellation started to dim abruptly in late 2019 and dimmed to less than a third of its usual brightness leaving astronomers puzzled about the reason behind it.

You should be thinking about why this event – “Great Dimming of Betelgeuse” – causing so much confusion. Well, let me tell you stars do change their brightness over the lifespan but this is measured in centuries, not months. Hence some astronomers thought that the Betelgeuse is dying and is about to explode in a supernova. But that never happened, instead it returned to its regular brightness levels in April 2020.

The mystery of "Great Dimming of Betelgeuse" solved by Astronomers
Event of Great Dimming of Betelgeuse from Jan 2019 to Mar 2020

This event left astronomers thinking about what could exactly be the cause of the “Great Dimming of Betelgeuse.” And they started assuming that unknown dust clouds or massive cool regions called starspots could be hiding the path of its light. Surprisingly in new research, published in Nature, astronomers from the Center for Astrophysics analyzed the images of the star and concluded that it was both – dust clouds and massive cool regions.

Mystery behind Great Dimming of Betelgeuse

Emily Canon, co-author of the study justified that “Great Dimming of Betelgeuse was the result of a cool spot on the star, an outcome of local drop in temperature. Which made the heavier elements like silicon present in a big bubble of gas that the star ejecting earlier, to condensed into dust initially making the star look dimmer.” Emily added, “This condensation added an instant drop in the brightness of the star.”

The research team used European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile and combined it with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument to directly image the surface of Betelgeuse, and then combined that with data from the GRAVITY instrument on ESO’s Very Large Telescope Interferometer (VLTI).

“With the ability to reach unparalleled spatial resolutions, the ELT will enable us to directly image Betelgeuse in remarkable detail,” said Emily Cannon, from KU Leuven. “It will also significantly expand the sample of red supergiants for which we can resolve the surface through direct imaging, further helping us to unravel the mysteries behind the winds of these massive stars.”

Is Betelgeuse Likely to go Supernova?

A heated topic of debate is whether Betelgeuse is likely to go supernova, because it is 15-20 times as giant as the sun and any object that big is likely to go supernova at any point, hence it was not hazy to speculate the death of the star and prepare to witness a spectacular explosion.

But unfortunately, to watch Betelgeuse go supernova, we need to wait another 100,000 years. As the star is young and has tens, hundreds, or thousands of years yet in hand. 

Discoveries are being done with every passing day and after solving the mystery of Great Dimming of Betelgeuse astronomers have high hopes from VLT to wrap up such mysteries as quickly as possible.


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