Oort cloud may be home to a captured exoplanet

The Oort cloud may be home to planet-like bodies trapped by the gravity of our Sun. This conclusion was reached by a team of researchers from France and the USA.

Planets in the artist’s image. Source: Caltech/R. Hurt (IPAC)

Currently, all the planets of the Solar System are moving in stable orbits. But this was not always the case. At the dawn of its existence, it went through a period of instability, accompanied by a change in the orbit of Jupiter. This perturbation threw out a significant part of the debris remaining after the formation of the Solar System. Some of them moved to remote orbits in the Oort cloud, and some left its limits forever. Some scientists even admit that in this way the Solar System could lose an entire planet. 

Most likely, this is a fairly common scenario. This is confirmed by the interstellar asteroid Oumuamua and comet Borisov, which visited our Solar System. Astronomers have also managed to find a number of rogue planets that move in free flight mode along the Milky Way. 

But if stars can catapult planets into space, are they also capable of capturing bodies ejected from other systems by their gravity? To answer this question, an international team of researchers resorted to the help of computer modeling.

The study has shown that about 10% of the planets initially included in the stellar system can later be thrown into interstellar space. As for the possibility of gravitational capture of such bodies, the best chances for this arise not when passing through the center of the system, but when passing through its distant boundaries.

As for our Solar System, according to the simulation results, there is about a 7% probability that a captured icy exoplanet may be in the Oort Cloud. For comparison, the probability that it can be home to a “native” planet that has moved to a remote orbit is only 0.5%. This means that if the hypothesis about the existence of planet X is correct, then with a very high probability it will be a body captured by solar gravity from another star system.

According to https://phys.org

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