Using the ultraviolet/optical telescope on board the NASA Observatory Nila Gerels Swift, astronomers discovered Gidroxil gas (it) – a chemical imprint of water – from the 3I/Atlas interstellar object.
The composite images of the 3I/Atlas interstellar comet, obtained using the ultraviolet/optical telescope on board the NASA Gerels Swift Observatory: the first were received on July 31 and August 1, 2025 (visit 1, the upper half of the drawing), and the second on August 19, 2025 (visit 2, the lower half of the drawing). The image is provided: syn and others.., two: 10.3847/2041-8213/ae08ab.
The opening of the third interstellar object, 3I/Atlas, on July 1, 2025 laid the foundation for a wide campaign in its characterization around the world.
Following the lessons extracted from the previous interstellar objects 1I/'Oumuamua and 2I/Borisov, the observation campaign was started to quickly fix its original brightness, morphology, shine curves, color, as well as an optical and close infrared spa.
Given the apparent brightness and early distribution of a coma, the release of gas was supposed and it was searched, but not found.
The characteristic of the early activity of interstellar objects is important for understanding their chemical and physical evolution during rapprochement with the Sun, since this may be the first time when they were significantly heated for their very long dynamic life.
“The detection of water is a major breakthrough in the understanding of how interstellar comets are developing,” Dennis Bodevits and his colleagues told the Astrona University of Obernie.
“In the comets of the solar system, water is a criterion by which scientists measure their general activity and monitor how sunlight stimulates the release of other gases.”
“This is a chemical criterion on which each comparison of the bats in the comet’s nucleus is based.”
“The detection of the same signal in the interstellar object means that for the first time we can start placing 3I/Atlas on the same scale that is used to study the comet of the solar system is a step towards comparing the chemistry of planetary systems in our galaxy the Milky Way.”
“What makes 3I/Atlas noteworthy is where the water activity occurs.”
Swift discovered a hydroxyl when the comet was almost three times further from the sun than the earth (significantly outside the area where water ice on the comet can easily be sublimate), and measured the water loss rate of about 40 kg per second. At such distances, most comets of the solar system remain quiet.
A strong ultraviolet signal from 3I/Atlas suggests that something else works here: perhaps sunlight heats small ice grains released from the core, allowing them to evaporate and feed the surrounding cloud of gas.
Such vast water sources were seen only on a few distant comets and indicate complex layered ice, which store the key to unraveling how these objects formed.
Each interstate comet discovered to date reveals different sides of planetary chemistry outside our sun.
Together they demonstrate that the building blocks of comets – and the flying ice that form them – can vary greatly from one star system to another.
These differences hint at how diverse the medium of the formation of the planets and how processes such as temperature, radiation and composition, form materials from which the planets and possibly life are ultimately arise.
To catch this whisper of ultraviolet light from 3I/atlas itself was a technical triumph.
SWIFT has a modest 30-centimeter telescope, but in orbit over the atmosphere of the Earth it can see ultraviolet waves that are almost completely absorbed before reaching the Earth.
Free from the glare of the sky and interference of the air, the ultraviolet/optical telescope of the swift reaches the sensitivity of a 4-meter-high-end terrestrial telescope for these waves of waves.
Her ability of quick guidance allowed astronomers to observe the comet for several weeks after the opening – long before it became too weak or too close to the sun so that it can be studied from space.
“When we find water – or even its weak ultraviolet echo – from the interstellar comet, we read a note from another planetary system,” said Professor Bodyvits.
“This tells us that the ingredients of the chemistry of life are not unique to us.”
“Each interstellar comet has still been a surprise,” added Dr. Zexsi Sin, postdoxterant from the University of Offer.
“Oumuamua was dry, Borisov was rich in carbon monoxide, and now Atlas gives water to such a distance where we did not expect this.”
“Each of them rewrites what, as we thought, we knew how planets and comets are formed around the stars.”
A paper Description of the results was published on September 30 in the journal Letters in the Astrophysical Journal.
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Jesi Sin and others.. 2025. The speed of water production by interstellar object 3I/atlas. April 991, L50; Two: 10.3847/2041-8213/AE08AB
