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

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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.