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

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.

The proposal concerns work that will have impact on various industries that directly benefit from the spin-offs of our research methodologies, expertise and in-house computer codes. For example, the research exploiting our state-of-the art multi-fluid models is extremely relevant in a surprisingly wide range of applications. These include the gas industry where our codes are used to simulate flows along pipelines and potential hazards associated with carbon sequestration, water management through simulations of river flow, and metallic paints. Other direct industrial beneficiaries are the mining and explosives companies that are being aided by the application of methods developed to model the explosion of stars as supernovae. Similarly, the combustion processes in supernovae have helped research into more efficient fuel combustion for the automotive industry. The ongoing development and improvement of computational methods and codes will ensure the continuation of existing, and the forging of new, fruitful industrial collaborations which will ultimately aid the UK's economic competitiveness.

The study of the extreme atmospheres on bodies such as Saturn's moon Titan will further help our understanding of the gases, aerosols and hazes in our own atmosphere. This will benefit the health of the population in general due to a better understanding of air pollution. Techniques devised to study planetary atmospheres are also being developed to better understand our own atmosphere and climate change in particular.

Our astronomical expertise has been applied to planning applications seeking to install infrared lighting near a dark sky park. This will ensure that both the population of that area are safe and that the public can still enjoy viewing the stars.

The subjects of stellar birth and planet formation, including their astrobiological relevance, appeal to the imagination. Leeds astrophysicists are strongly committed to communicating both their own and general astronomical results to a wide audience. They do this via public appearances and the organisation of events, and through the mass media by, for example, issuing press releases and making media appearances.

Our outreach is built around a set portfolio of events which continue to be developed and improved. We particularly focus certain events on school children and young people. An enhanced collaboration with the Leeds Amateur Astronomical Society is being established through the donation of telescopes and joint outreach events such as Stargazing Live.

A major new outreach venture is being planned at the site of the old British Telecommunication site at Goonhilly, Cornwall. The University of Leeds is leading a consortium of universities that is investing in, and work with, a private company that has taken ownership of the site. It is being redeveloped for commercial satellite telecommunications, deep space communications and radio astronomy. A key part of the plan is for a new visitor centre and space science park that aims to attract 100 000 visitors per year. This will showcase the best of British space science and astronomy to a new audience. Experience gained in reusing old infrastructure at Goonhilly for science will also be applied to Africa where many ex-telecommunications dishes are ear-marked for redevelopment. Leeds astronomers will play a key role in training new generations in developing countries.