Astronomers claim to have finally solved the mystery of why one of the most recognized and brightest stars in our sky suddenly began to dim a little over a year ago.
Betelgeuse, a red supergiant star in the constellation Orion, suddenly darkened in late 2019 and early 2020.
That behavior generated speculation that could be about to explode .
However, a team of scientists using the Very Large Telescope (VLT) in Chile affirms that the cause is most likely due to a gigantic cloud of dust that passes between the star and us.
Even if you can’t name many places in the sky, you can definitely identify Betelgeuse with the naked eye.
It’s the orange dot in the upper right corner of Orion (the Hunter), or in the lower corner right if you are observing from the Southern Hemisphere.
Betelgeuse is relatively close to Earth, about 550 light years, and is known as a semi-regular variable star. Glows and darkens naturally over a period of more or less 400 days.
But what happened a year and a half ago was out of the ordinary. The loss of brightness was much greater than ever had recorded .
Astronomer Miguel Montargès and his colleagues investigated the event through the VLT of the European Southern Observatory (SEO).
It is one of the most powerful telescopes on Earth , which is located in the Atacama desert, Chile and has sufficient resolution to p To produce a direct image of the Betelgeuse surface.
The researchers made a comparison of the images from before, during and after the dimming and projected models to see what kind of behavior could result in the observations obtained.
There were two ideas that dominated. Perhaps it was a large cold region on the surface of the star , because red supergiants like Betelgeuse are known to have large convective cells that can generate hot spots and cold spots.
On the other hand, perhaps there was a cloud of dust that was forming in front of the star from our perspective on Earth.
The explanation turns out to be “a bit of both”, according to Emily Cannon, an astrophysicist at KU (Katholieke Universiteit) in Leuven, Belgium.
“ Our general idea is that there was a cold zone in the star that, due to a local decrease in temperature, caused a previous gas expulsion to condense into dust, ”he explained to BBC News.
“So, the cold zone on the surface would make us see the star less luminous. But later, this condensation of the dust would increase the rapid dimming of the star. ”
Betelgeuse has a mass between 15 Y 20 times greater than that of the Sun . An object of that size is likely to go supernova at some point.
So it was not unreasonable to consider that when the unusual dimming occurred Betelgeuse could be close to exploding spectacularly .
” I don’t think this event means that Betelgeuse is going to go supernova anytime soon, although that would be incredibly interesting and I was almost looking forward to it! ” acknowledged Emily Cannon.
“We know that red supergiants can manifest an increase in the rate of mass loss, which may be an indication that there is a later stage in their lives where they could become supernovae. But we think that Betelgeuse is a relatively young red supergiant and probably has a lot more time left. ”
And how long is that? Tens, maybe hundreds or thousands of years is the time that astronomers usually cite.
It would be something very spectacular to see; the event would be visible in daylight.
The last supernova to be observed in the Milky Way , our galaxy , was the star Kepler, observed at . The records of the astronomers of the time say that it was visible during the day for more than three weeks.
The report of the investigative team of Miguel Montargès was published in the specialized magazine Nature .
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