The strange object of Oumuamu originated from a planet similar to Pluto, it flew from an alien system – ČT24 – Czech Television

Arizona State University astrophysicists have now explained Oumuamua’s strange features by saying that it is probably a piece of Pluto-like planet in another solar system. They informed about it in couple works v časopise AGU Journal of Geophysical Research: Planets.

“In many ways, Oumuamua resembled a comet, but in several ways it was so strange that speculation about its origin was in full swing,” said lead author Steven Desch. From the observation of the object, the scientists were able to describe several properties of the interstellar visitor, which were completely different from what would be expected from a comet.

In terms of speed, the object entered the solar system more slowly than might be expected. This suggests that he did not move in interstellar space for more than a billion years. In terms of size, its shape was also more flattened than any other known object in the solar system.

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Perhaps the most mysterious phenomenon was that the object gained a slight distance from the Sun during its passage through the Solar System. This is an effect also known for comets, but in the case of Oumuamua it was significantly stronger – it was this that led some scientists to conclude that it may have been the work of an intelligent civilization that changed its path on its own.

The answer hidden in the ice

The authors of the new work concluded that Oumuamua is made up of several types of ice with different properties. They also calculated how quickly these ice sublimes (that is, from solid to gaseous) as Oumuamua flew past the Sun. And it was from this that they calculated other properties of the object, including its weight, shape and explanation of why it could change its path.

“It was an extremely exciting moment for us,” Desch said. “We realized that a piece of ice would reflect much more light than expected. And that means it can be smaller, “said the astrophysicist. It was the sublimation of the ice that probably also affected the change in trajectory – thanks to the so-called rocket effect known from comets. This is because the sublimating ice has a relatively weak effect on the orbit of the body – in comets, but unexpectedly strong in Oumuamua according to new calculations.

According to the study, nitrogen in the form of ice has the main credit for this. If the object was created for the most part by him, all ideas about appearance, speed and other properties then correspond to the equations. At the same time, this material clearly brings to the origin of Oumuamua. There is solid nitrogen ice on the surface of Pluto – it is possible that an object resembling a comet could have formed from a similar body, only in a different star system.

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The reflectivity of Oumuamu corresponds to the values ​​measured on Pluto and Triton –⁠, and also this month of Neptune is formed on the surface by nitrogen ice.

“Oumuamua was probably thrown from the surface of a similar body by an impact about half a billion years ago and then expelled from its parent system,” the astrophysicists said. According to them, the unusual shape of Oumuamua also explains the fact that it is made up of frozen nitrogen: as the outer layers of nitrogen ice have evaporated, the shape of the body has gradually flattened, just as with a bar of soap when the outer layers rub off during use.

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