Scientists first decoded data, indicating chemical composition of the nucleus of comet Borisov. It turned out that he is not like the composition of comets of the Solar system. The study is published in the journal Nature Astronomy.
Comet 2I/Borisov — the second after an asteroid Omwamwi space body flew into the Solar system from the interstellar medium. Initially, the astronomers said that its composition is in General identical with the comets of the Solar system, but more detailed observations performed on a set of radio telescopes ALMA, located in Chile’s Atacama desert, showed that it is not.
“This is the first time we looked inside the comet from outside the Solar system — presented in a press release from the National radio astronomy Observatory in the words of one of the leaders of the study Cordiner Martin (Martin Cordiner), astrochemical from space flight Center name Goddard NASA, and it differs sharply from most other comets we’ve seen before.”
Complex ALMA for the first time made direct tests of the chemical composition of the gas emitted by comet 2I/Borisov on 15 and 16 December 2019. Astronomers have detected hydrogen cyanide (HCN) and carbon monoxide, or carbon monoxide (CO). The latter was present in very large quantities — in 9-26 times higher than that of comets in the Solar system, located at a similar distance from the Sun — within 2 and.e. or less than 300 million miles away. According to the researchers, this suggests that the comet Borisov formed in an extremely cold environment.
“The comet must have formed from a material very rich in CO ice, which is present only at very low temperatures found in space, below -250 degrees Celsius,” says the second study leader, a scientist, a planetary scientist Stephanie Milam (Milam, Stefanie).
Comets are interesting because their internal structure, unlike the planets, have not changed significantly since their birth. So they could tell a lot about the processes that occurred during their birth in a protoplanetary disk.
Carbon monoxide is one of the most common molecules in space, it is in most comets. However, there is a huge variation in the concentrations of co in comets of the Solar system, and nobody knows why. In part, this may be due to where in the Solar system was formed or that the comet, or how often a comet due to its orbital parameters closer to the Sun, the heat of which evaporates from the surface of the comet’s carbon monoxide.
In many respects the discovery was made possible thanks to the unique technical capabilities of ALMA is the first telescope that was able to measure the content of substances in gases originating directly from the core of the object, which came to us from other planetary systems.
“Only thanks to the unprecedented sensitivity of ALMA at submillimeter wavelengths, we can characterize the gas emerging from such unique objects,” explains another author Anthony Remijan (Anthony Remijan) from the National radio astronomy Observatory.
According to the authors, the comet 2I/Borisov formed far from their parent stars, in a cold region of ice bodies, which can be compared to the Kuiper belt in the Solar system, located beyond the orbit of Neptune. About planetary system in which star a comet appeared, we can only speculate, the researchers say.
“Most of the protoplanetary disks observed by ALMA are found around young stars with low mass such as the Sun, explains Gardiner. — Many of these discs extend far beyond the region where it is believed, formed our own comet, and contain a large number of extremely cold gas and dust. It is possible that the comet 2I/Borisov came to us from one of these large disks”.
The high speed at which the comet passed through the Solar system — about 33 kilometers per second, giving astronomers reason to believe that she was thrown out of his system in interaction with a passing star or giant planet. Then she spent millions or billions of years in the journey through the cold interstellar space, before August 30, 2019 saw the Russian Amateur astronomer Gennady Borisov.