The formation, structure, and evolution of molecular clouds, stars, and planets

我们的研究重点是提高我们对恒星和行星如何形成的理解，以及发生在恒星和行星内部和外层深处的物理过程。我们打算通过计算机建模和观测相结合来实现这一目标。恒星是从分子云中形成的，我们将研究这种湍流气体的结构，因为这对它们在重力作用下如何坍缩有很大的影响。我们将使用在亚毫米波长下进行的广泛调查来研究附近的星星形成区域环，称为古尔德带，测试我们的恒星形成模型，并寻找原恒星最早阶段的证据。我们还将使用计算机模型来研究古尔德带是如何形成的，因为超新星爆炸可能是形成其环状结构的关键。分子云的坍缩导致了具有各种质量的恒星群。大多数恒星的质量小于太阳，有些天体的质量很低，以至于它们的核心不会融合氢。这些物体被称为褐矮星，它们在形成时是热的，但随着时间的推移会变冷。通过研究星团的统计特性，我们将能够测量恒星质量的初始分布，这将使我们能够测试褐矮星是如何冷却的。虽然大多数恒星的质量小于太阳，但有些恒星的质量可以超过太阳的20倍，并且非常明亮。这些巨星的形成基本上是引力和星光施加的向外压力之间的竞争。我们将使用计算机模拟来研究这些恒星是如何形成的，并将我们的模拟与地面和太空望远镜的观测结果进行比较。我们将使用干涉测量法，一种将几个望远镜收集的光结合在一起的观测方法，来测量这些圆盘的结构。先进的计算机模型将被用来研究原恒星盘的相互作用。众所周知，行星是在这样的圆盘中形成的，我们将使用复杂的计算机模型来模拟原行星如何从尘埃和气体中合并出来。一旦星星和行星系统完全形成，剩下的唯一尘埃是由小行星碰撞在一起产生的，即所谓的碎片盘。我们将使用自适应光学（一种高分辨率的观测技术，用于校正地球大气层的扭曲效应）来识别年轻恒星周围新形成的行星，并研究这些系外行星对碎片盘的引力效应。我们将研究所谓的热彗星--受到其宿主恒星强烈辐射的系外行星的大气层。这项研究使用了英国气象局的地球气候计算机模型，该模型经过特别调整，以处理系外行星大气中发生的不同物理过程。我们还将使用计算机模型来研究木星和土星的内部结构，这些行星的形状因其快速旋转而扭曲。我们将把我们的结果与朱诺号和卡西尼号太空探测器的观测结果进行比较。太阳风是从太阳流走的连续等离子流。太阳和太阳风的大扰动影响我们的气候，并造成例如通信中断、停电和跨大西洋航班受到辐射。我们将使用理论和观测相结合的方法来研究太阳的物理学。我们将研究太阳磁场的性质，在太阳和地球附近的太阳风，表明它可以扭曲和扭结的方式。扭曲的积累可以导致太阳活动的增强，这对空间天气的预测有影响。我们还将使用计算机模型来研究电离气体与太阳磁场相互作用时太阳中的湍流运动是如何产生的。

Our research is focussed on improving our understanding of how stars and planets form, and the physical processes that occur both deep in the interior and in the outer layers of stars and planets. We intend to achieve this goal using a combination of computer modelling and observations.Stars form from molecular clouds, and we will examine the structure of this turbulent gas, since this has a strong influence on how they collapse under gravity. We will look at a nearby ring of star forming regions, called the Gould Belt, using an extensive survey taken at sub-millimetre wavelengths, testing our models of how stars form and looking for evidence of the earliest stages of protostars. We will also use computer models to investigate how the Gould Belt formed, since it may be that supernova explosions are the key to creating its ring-like structure.The collapse of a molecular cloud results in a cluster of stars with a variety of masses. Most stars are less massive than the Sun, and some objects have such low masses that they do not fuse hydrogen in their cores. These objects are known as brown dwarfs and they are hot when they are formed but cool over time. By examining the statistical properties of clusters of stars we will be able to measure the initial distribution of stellar masses, and this will enable us to test how brown dwarfs cool. Although most stars are less massive than the Sun, some can be over twenty times as massive and are extremely bright. The formation of these giant stars is fundamentally a competition between gravity and the outward pressure exerted by the starlight. We will use computer simulations to investigate how such stars form, and compare our simulations to observations from ground- and space-based telescopes.Newly forming stars are surrounded by dense discs of dust and gas. We will use interferometry, an observational method that combines light collected by several telescopes together, to measure the structure of these discs. Sophisticated computer models will be used to investigate the protostar-disc interaction. It is known that planets form in such discs, and we will use sophisticated computer models to simulate how a proto-planet coalesces out of the dust and gas. Once the star and planet system has fully formed, the only dust that is left is generated by asteroids colliding together, a so-called debris disc. We will use adaptive optics (a high-resolution observational techniques that corrects for the distorting effect of the Earth's atmosphere) to identify newly formed planets around young stars and examine the gravitational effect of these exoplanets on the debris discs.We will investigate the atmospheres of so-called Hot Jupiters - exoplanets that are strongly irradiated by their host stars. This research uses the Met Office's computer model for the Earth's climate, which has been specially adapted to deal with the different physical process that occur in exoplanet atmospheres. We will also use computer models to investigate the interior structure of Jupiter and Saturn, planets whose shape is distorted by their rapid rotation. We will compare our results to observations made by the Juno and Cassini space probes.The solar wind is a continuous stream of plasma flowing away from the Sun. The Sun and large disturbances in the solar wind affect our climate and causes, for instance, communication drop-outs, power outages and radiation exposure on transatlantic flights. We will investigate the physics of the Sun using a combination of theory and observations. We will examine properties of the solar magnetic field, at the Sun and near Earth in the solar wind, that indicate ways in which it can twist and kink. Build up of twisting can lead to enhanced solar activity, which has implications for the prediction of space weather. We will also use computer models to look at how turbulent motions in the Sun are produced as the ionised gas interacts with the Sun's magnetic field.