The mystery of the nature of the first interstellar object, Oumuamua, appears to be nearing its end. A pair of Arizona State University (USA) astronomers found a natural hypothesis to explain all the specifics of the star that quickly crossed the solar system in 2017.
When it was discovered, it initially appeared to be an asteroid, but with a reddish tinge, similar to that found in objects from the depths of the solar system. In its brief passage, the star suffered a deviation in trajectory that indicated the release of gases as it approached the Sun, a common action for comets. However, no evidence of this sublimation of gases that form the famous tails in comets has been observed.
Nothing seemed to match the meager observations exactly. To explain it, they even came up with a peculiar composition of hydrogen ice, something that has never been seen before and was difficult to even theoretically imagine, to no avail. These disagreements led Abraham Loeb, director of Harvard’s astronomy division, to argue that it was an alien spaceship.
Now Alan Jackson and Steven Desch have taken a decisive step towards ending the charade: in some articles published in the Journal of Geophysical Research: Planets, they put all the pieces together to explain what Oumuamua could have been and his Reconstruct past history.
Apparently it is a small piece of a star like Pluto, but it is from a young planetary system. A collision some 400 million years ago would have ejected the object from almost pure nitrogen ice (a common material found on the Plutonic surface), giving it the characteristic speed at which it entered the solar system.
In getting closer to the sun, it lost much of its original material that had sublimed into space. This wear and tear left it more and more in the form of a wafer that was thin in one dimension (like the way a soap wears unevenly with repeated use). This explains the observed rotation patterns and brightness fluctuations.
When astronomers were able to see it back in October and November 2017, it already had this very peculiar shape, like a round wafer 45 m in diameter and 7.5 m thick. The loss of matter helps its deviation from the trajectory explain, and the fact that the composition is nitrogen indicates why this process has not been demonstrated. The presence of a small amount of methane, which is also common with Pluto, could explain its red color. Everything fits.
Is that the end of the story? Not yet. To confirm the hypothesis once and for all, it will be important to observe other objects like him in the future. Even so, the solution to the puzzle seems to be in full swing for the first time.
This column is published in Folha Corrida on Mondays.
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