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In June 2021, astronomers Pedro Bernardinelli and Gary Bernstein discovered something strange while reviewing a series of archival photographs from 2014: a small dot moving rapidly through space. The images, made by the Dark Energy Observatory in Cerro Tololo, Chile, left little room for doubt. It was about a Kite, one unknown until then. And it was one of the big ones, although it was too far away to determine exactly its size, which was estimated at about 100 km. The comet was about 3,000 million km away and was approaching the Sun, shining more and more intensely.
Initial calculations revealed that the object, designated 2014 UN 271,
was born in the far Nube de Oort, the enormous space debris that surrounds the entire Solar System like a sphere, and that its closest approach to Earth would be around April 5, 2031, the date on which the comet will be located just outside the orbit of Saturn, somewhat more than 1,500 million km away. Just a week after the discovery, along with its official designation, the new comet was renamed Bernardinelli-Berstein in honor of its discoverers.
Now, a new and more precise estimate of its size, carried out by an international team of astronomers, has just determined that the comet is even greater than previously thought. With its 137 km long, in fact, the Bernardinelli-Bernstein has just been officially designated as the largest comet ever observed for the man A record that displaces the Hale-Bopp, of 74 km, from the first place in the list of the largest comets. The study on its size will soon appear in Astronomy and Astrophysics Letters, although the article can already be consulted on the pre-print server
arXiv.
For the new research, led by Emmanuel Lellouch, an astronomer at the Paris Observatory, the researchers used data taken by the Atacama Large Millimeter Array in Chile last August, when the comet was just over 2.9 billion km away. the earth.
As explained in their article, the researchers studied the microwave radiation emanating from the comet’s mass. And from these wavelengths of reflected light, the team was able to infer its size. Never before has this type of measurement been performed over such a long distance. Lellouch and his team believe that as it gets closer to the Sun, Bernardinelli-Bernstein will shrink significantly, as much material will melt and become part of its tail.
Unlike Hale-Bopp, which came much closer to us, the new comet won’t be visible to the naked eye, but scientists will still be watching it closely through their telescopes, trying to learn more about Oort Cloud objects. , a territory today virtually unknown.