200 light-years away ... the discovery of the "cosmic dance" of 5 planets
The European Space Telescope "Cubes" revealed that 5 of the distant outer planets of the Solar System, move in a regular and coordinated manner, as if they were performing a "dance".
It is a phenomenon that has not previously been observed among stars, whose diversity calls for a review of theories related to their formation, according to a recent study.
These planets, which were called exogenous due to their presence outside the solar system, revolve at the same level around their star "TOI-178" with a very precise time-regularity, about 200 light years away from Earth, according to Agence France-Presse.
These planets follow the movement of the "resonance chain" that the astronomer Laplace discovered at the end of the 18th century with three of Jupiter's moons.
Laplas found that the time required for one cycle of "Ganymede", which is the farthest, during which the closest planet, Europa, would make two rotations, while Io, which was closer to Jupiter, would run out 4.
The same mechanical movement applies to TWI-178, as the rotation of the first planet in the chain around the star takes about 3 days, while the following planets, each of which are farther from the previous one, need 6 days, then 10-15 and finally 20.
The alignment of some of them is coordinated regularly, and an animated film expresses the phenomenon, in which music accompanies the movement of these planets, and there is a sixth outer planet, which is closest to the star, rotating at a very high speed inconsistent with the following planets.
"We only know 5 other systems that operate according to this mechanism," in which a group of exoplanets co-ordinate in an orbital symmetry around their star, said lead author of the study, published this week in the journal Astronomics and Astrophysics, astronomer at the University of Geneva Observatory, Adrian Lilliou.
As for the astrophysicist at the University of "Bern", Yannick Alliber, who participated in the preparation of the study, he emphasized that the importance of the movement of these planets lies in the fact that they are probably still unchanged since they were formed, as if they were "a system frozen since the end of their formation phase that continues. Millions of years, as nothing has disturbed this "somewhat fragile" balance during the more than two billion years that followed this stage until today.
At this point, things get complicated. Usually, the density of the planets decreases as the distance from the star is, but the density of the third planet in the chain, in particular, is much higher than the density of the second, and Lilio noted that "there is a great diversity, which is surprising."
He added, "On the one hand, we have the impression that something has not moved over billions of years. The rotation periods of the planets are temporary with a difference of a few minutes, and they are regulated, and on the other hand we have these differences in density" that contradict the accepted theories regarding the formation of planetary systems.
It is assumed that monitoring will continue with the European Space Agency's "Cubes" telescope, which has been in Earth's orbit since December 2019 with the aim of determining initial specifications for planets outside the solar system, pending the use of its future successor, the "Hubble" telescope, which will be launched this year. And owned by James Webb