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https://www.ufonews.co/post/multiple-objects-detected-around-3i-atlas

"Anti-Tail" And Odd 594-Kilometer Feature Found On Interstellar Object 3I/ATLAS By Keck Observatory
October 16, 2025

Astronomers analyzing observations of interstellar comet 3I/ATLAS using the W. M. Keck Observatory have discovered further unusual features of our third interstellar visitor, and confirmed the presence of a rare "anti-solar tail".
On July 1, 2025, astronomers at the Asteroid Terrestrial-impact Last Alert System (ATLAS) spotted an object making its way through our Solar System. 
That's no surprise, given the name. What was unusual, and highly interesting, was that the object appeared to be the fastest object of this type ever observed, and had an eccentricity of between 6.1 and 6.2. 

An eccentricity greater than 1 means it is an interstellar visitor, the third we have found so far, and will leave our Solar System once more. 
It was named 3I/ATLAS to reflect that it is the third interstellar object discovered, as well as the team that found it in our skies. 
3I/ATLAS has been subject to (dubious) speculation that it is not a natural object. Astronomers have since been tracking the object, which was confirmed to be a comet due to its outgassing. 
Though there is little reason to suspect 3I/ATLAS is anything other than a natural object, it is of high interest to scientists and the public alike, having traveled alone through interstellar space for possibly 10 billion years.

In a new paper, which has not yet been peer reviewed, an international team of researchers analyzed the spectra of the comet, used to determine the elements present on the object and in its coma, as it was viewed by the Keck-II-mounted Keck Cosmic Web Imager on August 24.
"One avenue to understanding these objects is from cometary activity or lack thereof," the team explains in their paper, adding that the activity is caused by solar radiation heating the surface materials of the comet. 

"When a comet warms, its volatile ices sublimate, lifting dust off the surface and creating the coma. 
Sunlight excites these gas molecules, which then re-emit light by resonance fluorescence – revealing the composition of the volatiles. 
For Solar System comets, this provides a window into the primordial composition of the Solar System. Interstellar objects enable similar studies for otherwise inaccessible stellar systems."

By analyzing the spectra of light reflected off the comet, astronomers can figure out what elements and compounds it contains. 
We already have a few puzzles presented by 3I/ATLAS in this regard, with a previous paper finding it has an "extreme abundance ratio" of iron/nickel.
"Emission lines of FeI and NiI are commonly found in the coma of Solar System comets, even at large heliocentric distances. 
These atoms are most likely released from the surface of the comet’s nucleus or from a short-lived parent," the previous team explained in their paper. 
"The presence of these lines in cometary spectra is unexpected because the surface blackbody equilibrium temperature is too low to allow the sublimation of refractory minerals containing these metals."

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