A Research Programme on the Dynamics of Discs and Planets

圆盘和行星动力学研究计划

• 批准号: ST/H004173/1
• 负责人: Richard Nelson
• 金额: $ 6.39万
• 依托单位: Queen Mary University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FH004173%2F1
• 关键词: Research; Programme; Dynamics; Discs; Planets

The first bona fide planet orbiting a sun-like star outside of the solar system was discovered by a team of Swiss astronomers in 1995. Since this time, teams of international scientists have collectively discovered in excess of 350 extrasolar planets. Most of these planetary systems have very different architectures to the Solar System, raising many questions about how these planets formed and evolved. It is believed that planets form in the discs of gas and dust that are observed around young stars - so-called protostellar discs. Although there are significant uncertainties, a basic picture of planet formation has emerged. The first stage involves coagulation of small dust particles within the disc, which stick together when they collide to form larger pebbles. This process continues until larger bodies, with sizes approximately 10km, are formed. These bodies are called planetesimals, some of which are able to grow at a rapid rate through collisions with other planetesimals to form planets. At large distances from the central star, where the temperature in the protoplanetary disc falls to low values, water and other volatile compounds condense out of the gas to form ice grains. This has the effect of substantially increasing the amount of solid material, and allows very big solid planetary objects to form which can attract a large amount of gas from the disc to become gas giant planets, similar to Jupiter and Saturn. In the warmer inner regions of the disc, ice grains cannot form and so smaller rocky planets such as the Earth and Venus are expected to form. There are many theoretical uncertainties associated with each stage of the planet formation process described above, and the Isaac Newton Institute in Cambridge is hosting a four-month research programme aimed at solving some these outstanding theoretical problems. Most of the leading international researchers in this are will be attending the programme, providing a very exciting opportunity for making significant progress in understanding how planetary systems form and evolve.

1995年，瑞士的一个天文学家小组发现了太阳系外第一颗围绕类日星星运行的真正的行星。从那时起，国际科学家团队已经集体发现了超过350颗太阳系外行星。这些行星系统中的大多数都与太阳系有着非常不同的结构，这引发了许多关于这些行星如何形成和进化的问题。人们相信行星是在年轻恒星周围观察到的气体和尘埃盘中形成的-所谓的原恒星盘。尽管存在重大的不确定性，但行星形成的基本情况已经出现。第一阶段涉及圆盘内小灰尘颗粒的凝结，当它们碰撞时粘在一起形成更大的鹅卵石。这个过程一直持续到形成更大的天体，大约10公里。这些天体被称为微行星，其中一些能够通过与其他微行星碰撞以快速增长形成行星。在离中心星星很远的地方，原行星盘的温度福尔斯降到很低的值，水和其他挥发性化合物从气体中冷凝出来形成冰粒。这会大大增加固体物质的数量，并允许非常大的固体行星物体形成，这些物体可以从圆盘中吸引大量气体，成为类似木星和土星的气体巨行星。在圆盘较温暖的内部区域，冰粒无法形成，因此预计会形成较小的岩石行星，如地球和金星。上述行星形成过程的每个阶段都有许多理论上的不确定性，剑桥的艾萨克·牛顿研究所正在主持一个为期四个月的研究方案，旨在解决其中一些悬而未决的理论问题。大多数领先的国际研究人员将参加该计划，为在了解行星系统如何形成和演变方面取得重大进展提供了一个非常令人兴奋的机会。