For millions of years, the frozen traveler was silent through the stars, carrying secrets from another world. This summer, that interstellar visitor, now known as 3i/Atlas, passed through our solar system, only the third interstellar object that is known.
When astronomers at the University of Aubrus taught NASA Neil Gehrels High Observatory, they uncovered something incredible: a definite ultraviolet hydroxyl signature, a chemical water vapor by -product.
From the stars to open the water
The Auburn team leader Astrophysicist Zexi Xing used Swift ultraviolet vision to detect a low emissions of 3I/Atlas coma to confirm that the comet releases water. The results revealed that the object secretes about 1.36 × 10²⁷ water molecules per second or about 40 kilograms per second. It is even more surprising that this activity occurred when the comet was almost three times from the sun than the Earth is too cold so that most of the comes can lose water.
Stacking interwar comet 3i/atlas images purchased with goats, two visits. (Credit: Astrophysical Journal Letters)
This degree 3i/Atlas is rare in the company. There were few comes that contained such distant water sublimation when the sunlight is so weak that it would not dissolve the ice straight from the surface. The conclusion means that the water in the comet is instead transported by small ice grains, which are thrown into space, where even weak sunlight can evaporate them.
Ultraviolet advantage
Swift ultraviolet/optical telescope has given astronomers an advantage that terrestrial telescopes cannot: the ability to see the Earth’s atmosphere that has the most ultraviolet light and hides these subtle signals from the eye.
Being in orbit, Swift 2025 In the summer, he watched two sets of ultraviolet 3I/Atlas of images-at the end of July and again in mid-August. At a time when the two observations, the hydroxyl signal was almost doubled, showing that the water production increased dramatically as the comet approached the sun.
Because the spacecraft cannot seek to move targets, scientists used an area called motion correction, cutting data into 30 seconds to avoid images with a comet light. After loading the expositions together, scientists noticed a fog gas envelope around the nucleus, a clear sign that the water was liberated into space.
3I/Atlas radial surface brightness profiles V and UVW1 images for two observation visits. (Credit: Astrophysical Journal Letters)
Flow measurement
The steps were needed to determine how much water was emitted. Researchers began approximately how many hydroxyl molecules are located in the 10th or arc flow from the nucleus and July. About 2.2 × 10³⁰ molecules and 4.2 × 10³⁰ from mid -August were found. Based on the sunlight patterns, they calculated how quickly the water decomposes, and it ordered them to assess the final production speed.
Specifically, scientists have taken into account how the dust of the comet dispels the sun’s rays, adjusted what astronomers call “pink”. In addition, mild ultraviolet radiation can be misleading due to scattered light, not actual chemical action.
If the water found actually spreads directly from the surface of the comet, then at least 7.8 square kilometers or more than 8%of its surface must be actively emitted. It is an extremely large body with a nucleus radius of about 2.8 kilometers.
In most of our solar system, only 3-5% of its surface is active at one time or another. This amount of activity indicates that 3I/Atlas may have atypically ice density surface or that it is excreted in volatile dust grain, which continues to evaporate after being exiled.
Comparison interstellar visitors
This is a major breakthrough for astronomers investigating interstellar travelers. The first guest, 1i/’Oumuamua, had no signs of gas activity. The second, 2i/Borisov, released water and carbon monoxide in approximately equal amounts, and then returns to a mixture of carbon monoxide. Now, 3i/Atlas has once again reviewed the script, intensively water activities away from the sun and very few other volatile gas signs.
OH of molecules dependence on 10 ″ diaphragm and water production speed from red. (Credit: Astrophysical Journal Letters)
Infrared measurements have also revealed the frozen grains that have ordered it around it, suggesting that most of its water is obtained from a suspended material rather than a solid core. Comparing infrared and ultraviolet data, scientists were able to confirm that the emissions were out of the water, not nickel or carbon monoxide, which can mimic similar signs.
Each interstellar comet has a tale where it was formed. “Oumuamua was stony and dry, Borisov was rich in carbon, and the atlas is active in water, never seen in a distance. Such a variety indicates that planetary systems, except our own solar comet, under very different conditions.
Dennis Bodewits, a professor of physics in Aubrun and a co-author of the study, simplified it as follows: “When we see water or even his weak ultraviolet aid-the interstellar comet, we read a message from our planets system.
Window to the formation of the planet
This discovery also reveals how comes can carry water and organic molecules between galaxies. If bodies such as 3i/Atlas can endure frozen water for extended interstellar missions, it may be delivery vehicles for life ingredients between star systems. Unusual comet chemistry is water, but the poor for cyanogen (CN) is that it is formed from the substance in carbon dioxide, in the environment, near the youthful, metal poor stars.
As Xing noted, “every interstellar comet so far has been a surprise.” Oumuamua was dehydrated, Borisov was rich in carbon monoxide, and now the satin loses water from a distance where we did not expect. ‘
3I/Atlas Pink measurement. Left panel: 3I/Atlas measurements in literature compared to central measurement tape wavelength lengths. Right Shield: The same measurements converted into red -in, at the middle effective wavelength between V and UVW1. (Credit: Astrophysical Journal Letters)
3I/Atlas has not been visible since then, but will return after mid -November and give astronomers another opportunity to monitor its activities near the sun. Continuing observations with a space telescope could decide whether its water activity remains static or other gas occupies the most important place when the sun’s heating is strengthened.
Practical consequences of the study
Conclusions like these opens our eyes to the way water, and perhaps the blocks of life – through the universe.
By determining that interstellar bodies can preserve ice cream, which lasts millions of millions of years, the study gives us a deeper understanding of how the solar system begins and develops.
This increases the possibility that comet is space envoys by supplying water and organic compounds from one of the emerging world to another, potentially giving life to more than one corner of the universe.
Research findings are available online in the Astrophysical Journal.
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