A comprehensive study of stars, disks and exoplanets

Our research is focussed on improving our understanding of how stars, disks and planets form, and of the physical processes that occur deep in the interior of stars and in the atmosphere of exoplanets. We intend to achieve this goal using a combination of state-of-the art computer modelling and observations obtained from cutting-edge facilities. Stars form from molecular clouds which collapse, resulting in the formation of objects with a wide range of masses. High mass star formation may impact low mass star formation within the same cluster and the physical processes that are the most relevant during the formation of low mass stars and high mass stars, respectively, can be different. Forming the most massive stars is clearly a challenge because of the enormous radiation field produced by massive protostars. Many stars form in binary systems and newly forming stars are surrounded by dense discs of dust and gas. How binaries and how proto-planetary discs, which are the natural sites of planet formation, form precisely remain major unsolved problems. 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. Combining different observational methods at various wavelengths and sophisticated computer modelling that include complex physics, we will study in depth all steps, starting from the properties of molecular clouds, that lead to the formation of stars, discs and planets. After stars form, their further evolution is characterised by complex physical processes, such as turbulent convection and magnetism, that shape their internal structure and their observational properties. Exquisite observational data are now available, with for example asteroseismology providing important constrainsts on the internal structure of stars. We will use sophisticated numerical models to improve our understanding of stellar interiors and to explain various observational puzzles, such as the inflation of young stars or the large size of the convective core of hydrogen burning stars. We will also develop original strategies to optimise the detection of exoplanets by linking their presence to debris disks and to provide a comprehensive sample that enables exploration of exoplanet atmospheres over a wide range of orbital parameters. With the large number of exoplanets now available, a new era of wide-scale comparative planetology has now begun. We will carry out a comprehensive survey of highly-irradiated gas-giant exoplanet atmospheres with the Hubble Space Telescope and investigate major outstanding issues such as the atmospheric chemistry of cloud/haze formation. To describe the physical properties of exoplanet atmospheres, we use 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 develop new tools to understand the detailed atmospheric chemistry of irradiated exoplanets and which will be optimised to interpret observations. We will also analyse the climates of recently discovered nearby candidate habitable exoplanets (e.g. Proxima Centauri b) that may be characterised by observations from near future platforms, in order to explore the potentiality of these small planets to host some form of life.