The largest comet in history is rushing into the inner solar system. The latest observations indicate that the comet named 2014 UN271 is 150 kilometers in diameter. The last time it passed near us was about 3.5 million years ago.
In 2014, scientists discovered 2014 UN271 for the first time through the Dark Energy Survey (DES) program, and conducted nearly 40 observations on it in the following 4 years to estimate the size, speed, and trajectory. It shows that the 2014 UN271 orbit has a very high eccentricity (elliptical orbit).
However, it was not until June of this year that the Asteroid Center confirmed the existence of 2014 UN271, and pointed out that 2014 UN271 will come to an orbit close to Saturn in 2031, but because of the slightly farther distance at that time, it can only be judged that the diameter of the celestial body is between 100 and 370 kilometers. In the meantime, the orbital period is still uncertain.
Now, scientists have determined that 2014 UN271 is a super-giant comet with a diameter of 150 kilometers, approximately 17 times the size of an ordinary comet and 7 times the size of Phobos. Although future changes are still difficult to predict, when it approaches the inner solar system in 2031, new research shows that the brightness of 2014 UN271 in the night sky may be as high as 9th magnitude, almost as bright as Saturn’s largest satellite, Titan.
But if a layer of water ice forms on the surface of the comet, the brightness may drop a lot. In any case, this comet will undoubtedly become an interesting target for astronomical observation in the next ten years.
The new paper will be published in Astrophysical Journal Letters. The preprint of the paper is available on the ArXiv website.
(The first picture is a schematic diagram, source: Pixabay)
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