Interstellar comet 3I/ATLAS spews water like a cosmic fire hydrant

Comet 3I/ATLAS continues To be full of surprises. As well as just being Interstellar Object III The new analysis shows that it produces hydroxyl (OH) emissions, as these compounds reveal the presence of water on its surface. This discovery was made by a team of researchers at Auburn University in Alabama using NASA Neal Girls Swift Observatory, was described in a study published in Astrophysical Journal Letters.

Hydroxyl compounds can be detected by the ultraviolet signature they produce. But on Earth, the atmosphere blocks many wavelengths of ultraviolet light, which is why the researchers had to use the Neil Girls Swift Observatory, a space telescope free of the interference that observatories on Earth are subject to.

Water is present almost everywhere Comet They have been seen in the solar system, so much so that the chemical and physical reactions of water are used to measure, index and track these celestial bodies and how they interact with the heat of the sun. Finding it on 3I/ATLAS means being able to study its properties using the same scale used for ordinary comets, and in the future this information could be useful data for studying the processes of comets that originate in other star systems as well.

“When we detect water — or even the faint ultraviolet OH echo — from an interstellar comet, we are reading a note from another planetary system,” said Dennis Budewicz, an Auburn University physicist who participated in the research. press release. “It tells us that the components of the chemistry of life are not unique to us.”

Comets are Frozen masses of rocks, gases and dust Which usually orbit stars (the exceptions are the three interstellar objects found so far). When they are far from the star, they are completely frozen, but as they get closer, solar radiation causes their frozen elements to heat up and sublimate – turning from solid to gas – with some of this material being emitted from the comet’s nucleus thanks to the star’s energy. Formation of the “tail”.

But with 3I/ATLAS, the data collected revealed an unexpected detail: OH production by the comet was actually occurring farther from the Sun — when the comet was more than three times farther from the Sun than Earth — in a region of the solar system where temperatures typically aren’t sufficient to produce ice sublimation easily. However, already at that distance, 3I/ATLAS was leaking water at a rate of about 40 kilograms per second, a flow similar, as the study authors explained, to that of a “tap at full power.”

These details seem to indicate a more complex structure than is usually observed in comets in the Solar System. This could be explained, for example, by small fragments of ice breaking off from the comet’s nucleus, which are then evaporated by the heat of sunlight, feeding a gas cloud surrounding the celestial body. This is something that has so far only been observed in a small number of very distant comets, and which could provide valuable information about the processes from which 3I/ATLAS originated.

“Every interstellar comet so far has been a surprise,” Zixi Xing, a researcher at Auburn University and co-author of the discovery, said in his article. press release. “‘Oumuamua was dry, Borisov was rich in carbon monoxide, and now ATLAS is giving up water at a distance we didn’t expect. “Each one of them rewrites what we thought we knew about how planets and comets form around stars.”

This story originally appeared on Wired Italy It was translated from Italian.