Four years ago, astronomers detected “Oumuamua – the first known interstellar object to pass through our solar system. The object presented a series of strange and inexplicable features, some of which are consistent with a frozen shard torn from an object similar to Pluto, according to new research.
“We suggest that ‘Oumuamua was probably thrown from a young star system about half a billion years ago,'” say two new researchers in the Journal of Geophysical Research: Planets. Because the object features features seen on the moon of Pluto and Neptune, Triton, the authors, planetary scientist Alan Jackson and astrophysicist Steven Desch, both from Arizona State University, say “Oumuamua may be the first piece of an exoplanet brought to us.” .
Of course, what does that mean is that it is the first known piece of an exoplanet brought to us; and by exoplanet means an exo-dwarf planet, because Pluto is not technically a planet (if these corrections are not what they intended to say, then I say it should be).
In their work, Jackson and Desch classify Oumuamua as a “former Pluto,” which I think is pretty cool. Indeed, astronomers often compare exoplanets and other astronomical phenomena to those orbiting our Sun, referring to hot Jupiters, super-Earths, and sub-Neptunes, for example. We can now add “ex-Plutos” to the list of known astronomical objects and, by virtue of this, “Plutos” in general – small frozen worlds located in the Kuiper belts (another analogous term borrowed from our solar system) of distant star systems.
To this traveler he paid us a visit from afar, “we had no way of knowing if other solar systems had planets like Pluto, but now we saw a piece of a single passage on Earth,” Desch said in an AGU statement. Well, that’s assuming that this interpretation is correct, which, if it is, means “Oumuamua would be the first evidence that Pluto-like objects exist elsewhere in the galaxy.
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“Oumuamua did not stay long when he visited our neighborhood in 2017, as he traveled at speeds reaching 315,430 km / h. It is difficult to understand this type of speed, but to say that he traveled 54 miles every second (87 km / s) helps somewhat.
The interstellar object was fast, but it was also strange. “Oumuamua is quite small – about half the size of a city block – but exceptionally thin, having a depth of about 35 meters. So strange and unprecedented is this form that at least one scientist he said, “Oumuamua may not be natural at all and instead a kind of probe sent by aliens. The object is also very bright (i.e. it has a high albedo), has a weak comet coma and a slightly apparent acceleration rate not caused by gravity.
For the first of the two studies, Jackson and Desch considered several different types of ice that could exist on such an object. They did that to determine how the evaporation of ice could contribute to the observed non-gravitational acceleration of the object. Scientists have calculated how quickly these various frosts sublimated (when the solid changes directly into gas) when “Oumuamua passed our Sun. Factors such as mass, shape and reflectivity were also considered to explain the propulsion effect produced by sublimating ice.
Solid nitrogen proved to be the best match. This is a very interesting result, because Pluto and Triton are known for their solid nitrogen-rich surfaces. and for albedo similar to that described for ‘Oumuamua.
Nitrogen could also explain the unusual shape of the object. “Oumuamua had only recently taken on the appearance of pancakes, as a result it flew close to the Sun, according to the study. The resulting melting caused the object to lose more than 95% of its total mass and, as the ice evaporated, “the shape of the body would become more flattened, like a bar of soap as the outer layers were cleaned by use. Said Jackson.
In the second paper, the authors estimated the rate at which Pluto-like objects could have large chunks of ice ripped from surfaces during youth. They also estimated the rate at which these pieces would become interstellar and make their way to our solar system.
“A similar fragment, generated in another solar system, after traveling about half a billion years through interstellar space, would fit the size, shape, brightness and dynamics [‘Oumuamua]The authors wrote in the second paper. “The chances of detecting such an object, as well as more comet-like objects such as the interstellar object 2I / Borisov, are consistent with the number of such objects we expect in interstellar space if most star systems were expelled. comets and [nitrogen] fragments of ice with the same efficiency that our solar system did. ”
The 2I / Borisov object, if you are wondering, was detected in 2019 and is the second known interstellar object let’s go through our solar system.
Matthew Knight, an astrophysicist at the US Naval Academy and an expert on “Oumuamua, was impressed by the comprehension of the two studies.
“The authors did an excellent job of meeting various theoretical and observational constraints with a simple, self-consistent model,” said Knight, who was not involved in the new research. in an email. “Their key idea, that ‘Oumuamua was composed primarily of highly reflective nitrogen ice, is both creative and satisfactorily plausible, as we have sufficient evidence that nitrogen ice is common on the surface of Pluto and other objects. large in the outer solar system. ”
Knight said these ideas have a good chance of finally being accepted as the best explanation for “Oumuamua.”
As it stands, we know only two interstellar objects, “Oumuamua and 2I / Borisov, but that could change soon due to the next Vera C. Rubin Observatory and the 10-year Legacy Survey of Space and Time.” project.
“It is anticipated that the LSST should find about one a year, so when we have 10 or 20 known objects, we will be in a much better position to make a statistical assessment, ”said Knight. “It will be very interesting to see how these results change our understanding of how our solar system works and reveal how similar – or not – our solar system is to other solar systems.”