Astronomers from Spain and Britain, as a result of observations of the most unusual comets, discovered the first traces of a star that flew through the solar system about 70 thousand years ago. This is stated in an article published in the Astrophysical Journal Letters.
“We calculated the orbits of many comets, which move in very elongated orbits, and found out from which part of the sky they fly towards the Earth. As a rule, such comets should be evenly distributed over the sky. Accordingly, their clustering at one point in the constellation Gemini suggests that Scholz's star flew through the solar system along this route, said Carlos de la Fuente Marcos, planetary scientist at the University of Madrid.
Four years ago, amateur astronomer Ralph-Dieter Scholz discovered what seemed to him quite an ordinary star - the red dwarf WISE J0720. Now it is in the constellation of the Unicorn, at a distance of about 20 light years - that is, it is one of the closest stars to Earth.
Two years ago, American astronomers found out that Scholz's star relatively recently - about 70 thousand years ago - flew through the solar system. She approached the Sun at a record close distance (about 1.9 light years) and at the same time changed the orbits of many comets and small celestial bodies in the far part of the Oort cloud.
According to de la Fuente Marcos, scientists have no doubt that the star really flew through the solar system, but it is not yet entirely clear how exactly this happened. Accordingly, it is impossible and accurate to assess how this visit influenced the orbits of the planets, including the Earth, where people left Africa at that time and began to colonize the rest of the continents.
The Spanish astronomer and his colleagues found the answer to this question and independently confirmed that the Scholz star did indeed visit the solar system. To do this, they analyzed the orbits of the so-called hyperbolic comets - small celestial bodies that move in a very elongated orbit around the Sun, then coming very close to it, then moving away to the outskirts of the Solar System.
As scientists have suggested, the approach of Scholz's star with the Sun should have changed the orbits of many comets in a special way, forcing them to go into hyperbolic orbits or even leave the limits of our planetary system. Accordingly, the trajectory of the star itself can be determined by detecting an unusual cluster of such comets in a certain part of the Oort cloud.
This idea, as de la Fuente Marcos notes, helped his team discover not only the point at which Scholz's star flew into the solar system, but also eight supposedly interstellar comets: comet Bruns (C / 1853 R1), as well as celestial bodies discovered by projects Spacewatch, SOHO, LINEAR and ISON.
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Their further study, scientists hope, will help to check whether this is really so and to obtain new data on the chemical and mineral composition of aliens from other stellar systems. If the predictions are confirmed, the asteroid Oumuamua will lose its status as the first interstellar celestial body, giving way to a comet discovered by Karl Bruns in 1853.