Illustration by Tag Hartman-Simkins / Futurism. Source: Getty Images
New analysis of an interstellar interloper to our solar system. 3I/ATLASshow that it spews huge amounts of water – and astronomers can't immediately explain why.
An object widely believed to be a comet exhibited strong ultraviolet emission that unmistakably indicates the presence of hydroxyl gas (OH), a byproduct of water, when astronomers photographed it with NASA's Neil Gehrels Swift Space Telescope before it disappeared behind the Sun. The emissions could only be detected from space because ultraviolet light was absorbed by the atmosphere.
Their findings, detailed in new research published in Letters from the Astrophysical Journal, argue that the presence of all this OH indicates that the comet is spewing out water vapor at a rate of about 88 pounds per second, which is roughly the speed of a fire hose running at full blast, according to press release about the conclusions.
What's most unusual is that it was seen quite far from the Sun, at a heliocentric distance of about three astronomical units (AU), or three times the distance between Earth and our star. Typically, comets fly much closer to the Sun before the water ice at their core, called the nucleus, begins to sublimate, or instantly change from a solid to a gas. Something else must be causing 3I/ATLAS to shed water – which also implies that the comet must contain significant reserves of water for this process to continue.
“When we detect water—or even its faint ultraviolet, OH, echo—from an interstellar comet, we are reading a note from another planetary system,” co-author Dennis Bodewits, a professor of physics at Auburn TK, said in a press release. “This tells us that the ingredients in the chemistry of life are not unique to us.”
This is yet another example of the fascinating strangeness of interstellar objects like 3I/ATLAS. Think of it as a sample of something very distant, perhaps tens of millions of light years, passing right past our doorstep. That it is largely bizarre compared to native comets hints at how unique these unimaginable alien kingdoms must be, and that we have yet to understand how star systems form and how their structures may evolve.
Typically, a cometary comet, a huge halo of gas and dust that gives comets their luminous appearance, begins to form as an object approaches the Sun (or presumably another star) and heats up. The heat either sublimates or vaporizes the core material at its center, which is many times smaller than the coma visible from the ground. As it moves, the coma extends behind the comet, forming its signature tail.
Coma 3I/ATLAS has already surprised us in many ways. Its chemistry strange compared to our cometsand it looks like he has surprisingly high carbon dioxide to water ratio.
What causes the release of water vapor is still unclear. Astronomers speculate that sunlight may heat the ice grains released from the core, which then evaporate into the surrounding coma.
Astronomers believe 3I/ATLAS arrived from the center of the Milky Way, where it was likely ejected from its original star system by a gravitational disturbance, such as the flyby of another star, and braved interstellar space before eventually flying through the vicinity of our solar system. Based on these findings, astronomers estimate that the comet must be billions of years old, perhaps three billion years older than the Sun itself. This is not only a snapshot of another part of the galaxy, but also of a different era of space altogether.
Right now, 3I/ATLAS is flying behind the Sun, so we can observe it from Earth. But scientists managed to see this with the help spacecraft located near Marsand will soon become fully visible again at the end of November.
“Every interstellar comet so far has been a surprise,” lead author Jiexi Xing, a postdoctoral fellow at Auburn University, said in the report. statement about work with reference to two previously discovered interstellar objects. “Oumuamua was dry, Borisov was rich in carbon monoxide, and now ATLAS is releasing water to a distance where we did not expect it.”
“Each of them,” Xing added, “rewrites what we thought we knew about how planets and comets form around stars.”
More about space: Astronomer: 30+ Percent Chance of Interstellar Object Is an Alien Ship Disguised as a Comet
