Oumuamua, the first alien "guest" of the solar system, took on a cigar-shaped form as a result of the fatal "encounter" of his progenitor with the giant planets in his home star system, scientists say in an article published in the journal MNRAS.
In mid-October last year, the automated telescope Pan-STARRS1 discovered the first "interstellar" celestial body. This object was tentatively named "comet", received the temporary name C / 2017 U1, and dozens of ground-based and orbiting telescopes began to follow it.
Before she left the near-earth space, scientists managed to get a lot of images and data on its physical properties, which indicated that this object is more an asteroid than a comet. It was renamed 1I / 2017 U1, and later received the name Oumuamua, which means "scout" in the language of the native inhabitants of Hawaii.
According to Sean Raymond from the University of Bordeaux (France), the unusual cigar-shaped shape and the very existence of this object made scientists wonder where this asteroid could have flown into the solar system, where it was born and what it was before "catapulting" into the interstellar Wednesday.
The fact is that the discovery of Oumuamua testifies to the fact that each star in the Galaxy throws out a huge amount of protoplanetary bodies and their debris that arise during collisions with other planets. Their mass certainly exceeds the weight of all asteroids and "embryos" of planets in a typical star system.
“Asteroids can form only in the warm part of the protoplanetary disk, where water evaporates. Its total area is almost zero, and it is extremely difficult to knock out asteroids from there, since the star's gravity acts on them more than on comets. It is extremely difficult to imagine how Ouamuamua could have been thrown out of his planetary family if he was originally an asteroid,”explains the planetary scientist.
Raymond and his colleagues figured out how to avoid all these problems with "space demography", if we assume that asteroids leave stellar systems not by themselves, but thanks to the "help" of one or more giant planets orbiting in unstable orbits.
Gas giants, as scientists note, can periodically approach large embryos of planets during their migrations through the star system. Under a certain set of circumstances, such a "rendezvous" will not only lead to the ejection of a protoplanetary body into open space, but also to its disintegration into many asteroids.
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Some of them end up in the interstellar medium immediately, while others get there during subsequent meetings with gas giants. Even if such a fate befell only 1% of protoplanetary bodies, the number of their debris, according to planetologists, will be enough for asteroids to dominate in outer space, not "homeless" comets.
Interestingly, such fatal encounters do not lead to the complete destruction of the "embryos" of the planets and their transformation into fine dust, but to their disintegration into a large number of fairly large objects, some of which will be similar in shape to Oumuamua's "cigar". The discovery of other "aliens" from the interstellar medium, as Raymond notes, will help us verify whether this is so or not.