A Programme of Astrophysical Research at Leeds

This research programme principally addresses how stars and planets form and evolve. Stars form from the clouds of gas that occupy interstellar space and the small dust grains mixed in them. The formation of stars much more massive than our Sun has proved to be much more difficult to understand 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. Detailed mapping of the molecular emission with the ALMA telescope will reveal whether these discs are stable or whether they will fragment to form binary systems. The inner regions of these discs are hotter and will be studied using the techniques of infrared interferometry and spectroscopy. This reveals 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, most likely driven by magnetic fields. To follow these jets further out we will use radio telescopes including the network of radio dishes in the UK, e-MERLIN, to map their emission. We will look for links between bursts of material falling on to the new star with ejections of material along the jets. The discs that surround stars like the Sun as they are forming are the sites where planets form, built up from the coalescence of dust grains. A survey of the properties of these discs around stars slightly more massive than our Sun will be carried out to study the phase when the leftover gas is being blown away and collisions between proto-planets is creating belts of dust. A high resolution study of the chemical make up of planet forming discs will be carried out with the ALMA telescope to look for complex organic molecules in the planet-forming and comet-forming outer reaches. These molecules could be important in the origins of life. A new survey of our Milky Way with the MeerKAT radio elescope in South Africa has revealed a network of filaments of emission. We will investigate this new phenomena in the interstellar gas and its relationship to sources of cosmic rays.