Researchers in New Zealand spotted a few days ago a sketch of a coma emerging from the giant comet C/2014 UN271, which continues to enter the System internal solar. As a reminder, it could be the largest comet ever observed to date.
Identified in Dark Energy Survey data captured between 2014 and 2018, Megacomet C/2014 UN271, also known as Comet Bernardinelli-Bernstein, is visibly beginning to "rubbing" in the Sun.
On June 23, New Zealand astronomers were the first to spot a coma, a halo of gas and dust released under the effect of stellar heat , causing the sublimation of the ices of its core. The images were captured from one of the Las Cumbres Observatory (LCO) telescopes hosted in South Africa.
"In our first image, the comet had been obscured by passing satellites, but the others were quite clear. It was there, definitely a beautiful little fuzzy point that contrasted with the sharpness of the neighboring stars “, explains Michele Bannister, from the New Zealand University of Canterbury.
When these first signs of activity were detected, the comet was approximately 19 astronomical units away (AU) of the sun. As a reminder, one AU is equivalent to the average Earth-Sun distance, i.e. approximately 150 million kilometres. For comparison, that's about twice Saturn's orbital distance from the sun.
Preliminary estimates suggest that the huge Bernardinelli-Bernstein nucleus is more than 100 km in diameter . This is about three times larger than the largest known cometary nucleus, that of comet Hale-Bopp which passed near Earth in 1998. C/2014 UN271 could also be the most massive comet ever recorded throughout history (a thousand times more massive than a typical comet).
2014 UN271 comes to us from the Oort Cloud, an ice cloud found well beyond the Kuiper Belt, between 5,000 and 100,000 AU from the Sun. The comet completes one revolution of our star in 612,190 years, and is expected to reach the closest point of this huge round trip in 2031, when it will pass less than 10.9 AU from the Sun . It will then have almost reached the orbit of Saturn.
Unfortunately, Bernardinelli-Bernstein will not approach close enough to our planet to be observed with binoculars. Several large telescopes on the ground and in space, as well as any nearby spacecraft, will be able to observe the object, allowing researchers to learn as much as possible about its composition and history. strong>
