赤道直径约为143,000公里，Jupiteris the largest planet in the solar system and has 300 times the mass of the Earth. The formation mechanism of giant planets like Jupiter has been a hotly debated topic for several decades. Now, astrophysicists of the Swiss National Centre of Competence in Research (NCCR) PlanetS of the Universities of Bern and Zürich and ETH Zürich have joined forces to explain previous puzzles about how Jupiter was formed and new measurements. The research results were published in the magazine Nature Astronomy.
Solar system divided into two parts
The new model for Jupiter’s birth matches the meteorite data that were presented at a conference in the US last year. At first, Julia Venturini and Yann Alibert were puzzled when they listened to the results. Measurements of the composition of meteorites showed that in the primordial times of the solar system the solar nebula was divided into two regions during two million years. It could therefore be concluded that Jupiter acted as a kind of a barrier when it grew from 20 to 50 Earth masses. During this period, the forming planet must have perturbed the dust disk, creating an over-density that trapped the pebbles outside of its orbit. Therefore, material from outward regions could not mix with material of the inner ones until the planet reached enough mass to perturb and scatter rocks inwards.
“How could it have taken two million years for Jupiter to grow from 20 to 50 Earth masses?” asked Julia Venturini. “That seemed much too long,” she explains: “That was the triggering question that motivated our study.” A discussion by email started among NCCR PlanetS researchers of the Universities of Bern and Zürich and ETH Zürich and the following week the experts in the fields of astrophysics, cosmochemistry and hydrodynamics arranged a meeting in Bern. “In a couple of hours we knew what we had to calculate for our study,” says Yann Alibert: “This was only possible within the framework of the NCCR, which links scientists from various fields.”
通过计算，研究人员表明，年轻地球在15至50个地球群众的群众范围内花费的时间确实比以前的思想长得多。在该形成期间，与公里型岩石的碰撞提供足够的能量以加热年轻木星的气态气氛，并防止快速冷却，收缩和进一步的气体增生。“鹅卵石在第一阶段很重要，以便快速构建核心，但是由行星提供的热量对于延迟气体增值至关重要，以便与陨石数据给出的时间级，”天体物理学家总结。他们相信他们的结果提供了解决形成的长期存在的关键要素Uranus和Neptune和exoplanets in this mass regime.
出版物：Yann Alibert，等，“通过杂交卵石 - 行星血管成像，”木星的形成“Nature Astronomy (2018)