In our solar system, the two outermost planets, Uranus and Neptune, are a bit strange. Although the masses of the two planets are similar, and the distances from the sun are similar, the orbits of the two planets and the way satellites and satellites orbit the satellites are significantly different. A new paper proposes a theory to explain why this is due to two different large-scale impact events that occurred during the formation process.
Christian Reinhardt, the paper's lead author, said in an article: "Despite the obvious similarities between the planets," there are amazing differences between the two planets that need to be explained. ". statement.
The first major difference between the two planets is their inclination. Like the Earth, most planets in the solar system have a slight title on their axis, so at different times of the year, part of the planets are closer to the sun, which is why we have seasons. Uranus and Neptune both Extremely long season, Lasting up to ten years.
However, the biggest difference is that Uranus' title is so high that it is almost completely aside. Co-author Joachim Stadel of the paper said in a statement: "Uranus and its major satellites are tilted about 97 degrees toward the solar plane, and the planets are effectively retrograde with respect to the sun."
Another difference is the satellites of the planets. Uranus and its satellites are all named at the same angle, which indicates that they are formed from disks, just like Earth's satellites. But on Neptune, Triton, the largest Triton satellite, orbits at an angle relative to the planet, suggesting that the moon formed elsewhere and was attracted by Neptune's gravity.
The paper suggests that these differences can be explained by the way planets are formed. Both started in similar situations, but were affected differently.
Researchers carried out computer simulations and found that the most likely cause of Uranus' tilt was that it was preyed by a large object that pushed the planet to the side without affecting its interior. In the case of Neptune, this planet appears to have a head-on collision, which does affect its interior, causing heat to move from the interior to the surface much faster than other planets.
"We clearly show that formation pathways initially similar to Uranus and Neptune may lead to the observation of dichotomy in the properties of these fascinating exoplanets," concludes co-author Ravit Helled.
Research results published in journal Monthly journal of the royal astronomical society.