A Programme of Research in Astronomical Theory, Astronomical Observations and Planetary and Solar System Science

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We address two key areas of astrophysics: how do stars form from clouds of dust and gas and what chemical processes are at work in our solar system that may play a role in the emergence of life. Magnetic fields pervade interstellar space and play a crucial role in controlling how material can accumulate into ever denser cores as gravity takes hold during the collapse to a star-planet system. Even though stellar birth sites are cold and dense there are still some charged particles such as electrons, molecular ions and, importantly, charged grains of dust. We will investigate with computer simulations how the presence of charged dust grains affects the formation of stars similar to our Sun.The formation of stars much more massive than our Sun has proved to be much more problematic as they are rare and distant and produce prodigious amounts of radiation that blow material away rather than let it fall in. As the infalling material gets close in to the star we expect it to complete its journey in a thin disc orbiting the star. We will search for these discs using the techniques of infrared interferometry. With imaging spectrographs we will look for tiny spatial shifts from spectral lines from the disc relative to the starlight to gain spatial information at levels 10 to 100 times better than the Hubble Space Telescope.At the same time that material is spiralling onto a star via a disc, some of it is being ejected at high speeds along the rotation axis by magnetic fields. We will use the highly sensitive new network of radio dishes in the UK, e-MERLIN, to map the emission from these jets and study how these plough into the surrounding infalling molecular material. The detailed mapping of the molecular emission will be carried out with the new ALMA telescope in Chile where 66 dishes work in unison at microwave frequencies. Combined radio and microwave studies will allow us to find out when the magnetic forces give way to the strong pressure of radiation.As massive stars finally begin to clear away the material from which they were born, the combined effect of the winds driven by their strong radiation fields has a dramatic effect. As the winds slam into the molecular material, and each other, they emit strongly in the X-ray region as observed with NASA's Chandra satellite. The most massive stars have such short lives of a few million years, that they can blow up as supernovae whilst still surrounded by the remnants of the molecular clouds. Computer simulations will be used to tackle this problem to investigate how these processes can terminate the star formation episodes in giant molecular clouds. In distant, primeval galaxies, massive star formation dominates much of what we see. Chemical models and observations will be used to help us understand how the first generations of stars evolve. Massive stars that are nearing the end of their lives also lose much of their mass due to the radiation pressure driving off their outer layers. These processes will be investigated observationally using the high resolution IR techniques described above. When two massive evolved stars are in a close binary system their winds also smash into each other giving rise to X-ray emission. Numerical simulations will be used to investigate these processes. Titan, one of Saturn's moons, is of great interest as there are analogies to the early Earth. The Cassini Huygens mission found that there is more benzene than expected in the atmosphere and less ethane on the surface (lakes rather than deep oceans). We will carry out a range of laboratory studies to determine the atmospheric rates of formation and removal of these species and gauge the impact of our results through inclusion in chemical models.Meteorites preserve a memory of the early solar system and their chemical make-up can help us understand the origins of life. Experiments on iron meteorites will investigate the role of electron transfer on pre-biotic molecules.