Astronomers from New Zealand have noticed signs of activity on C / 2014 UN271. It is considered the most massive of all known to mankind, being about a thousand times larger than an ordinary comet, according to a release from the University of Canterbury.
Studying space images, scientists noticed traces of a coma - clouds of dust and gas that surround the core. The photographs were taken when the comet was at a distance of 19 astronomical units from the Sun (1 AU is the distance between the Earth and the Sun).
Scientists noted that the comet did not look as clear as the stars, but blurry. This indicated the presence of a gas envelope surrounding it.
A coma forms when a comet heats up as it approaches the Sun. Under the influence of heat, particles on its surface sublimate (pass from a solid state to a gaseous state).
"Given the size of the comet's nucleus, the sun needs to heat up a large mass," the authors of the scientific work noted.
The comet was discovered during a project to search for dark energy. Its opening was officially announced on June 19, 2021. But signs of activity were only noticed now, which attracted a lot of attention from the scientific community.
Measurements have shown that the diameter of a cosmic body is from 100 to 370 kilometers, almost like a dwarf planet. The closest approach to the Sun will occur in 2031. But even then, the comet cannot be seen with the naked eye, despite its size and brightness - it will be at the same distance from the center as the planet Saturn.
The comet has a very long orbit. It approaches the Earth about once every 600 thousand years. Over the past year, it has overcome 7 AU. and in the future it will approach the Sun at a distance of 10, 9 astronomical units.
Scientists plan to study comets using robotic telescopes. They will help you find out why these space objects change brightness.