Physics & Astrophysics
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Research - an Overview
Our research in astrophysics is wide-ranging and covers observational and computational work on stars, planets, interstellar matter and galaxies. Below is a brief outline but further information is available on the Astrophysics Group website and the Astrophysics Research Centre.
The South African Large Telescope or SALT is the largest single telescope in the Southern Hemisphere, its 11-m mirror allowing unprecedented spectra of faint sources while giving spectra of exceptional quality of brighter sources. As a SALT partner, Keele is entitled to several nights per year of queue-scheduled time.
The Wide Angle Search for Planets (WASP) is undertaking a comprehensive, wide-field sky survey to detect planetary transits in stars down to 18th magnitude. With greatly increased numbers of known extra-solar planets we will investigate the accretion processes that lead to planet formation, and thus better understand the origin of our own home. WASP will also provide a wealth of data on all classes of variable stars, allowing the systematic analysis of large samples and the discovery of new and rare variable types.
When a star like the Sun exhausts its fuel its internal structure undergoes major changes and it moves away from the main sequence of the Hertzsprung Russell diagram. This research involves using infrared and sub-millimeter telescopes to probe the latter stages of stellar evolution, particularly those stars that evolve on the timescale of a human lifetime.
Accretion is one of the most widespread and important phenomena in the universe. Keele's programme investigates accretion onto the supermassive black holes that reside in the centres of galaxies, and the outflows that result from this process, using satellites such as XMM and Chandra.
Stars like the Sun or of even lower mass are born in clusters and associations. We search for young Suns, low-mass stars and brown dwarfs in star forming regions and clusters in order to find how common they are in a variety of environments and follow the temporal evolution of their discs, rotation rates, magnetic activity and chemical abundances. Our goals are to understand the way in which birth environment influences the development of low-mass stars (and their planetary systems) and to investigate the astrophysics, such as mixing, convection and magnetic fields, that are incorporated into pre main sequence evolutionary models.
Most of the current activity at Keele in the field of stellar ecology comprises large observational programmes (mainly imaging and spectroscopy at optical and infrared wavelengths on 4-8m class telescopes) to study the mass loss and evolution of red giants and supergiants in the Magellanic Clouds and in more distant spiral galaxies, as well as supernova remnants, the interstellar gas and dust, and the process of formation of new stars and the associated chemistry.
Binary stars have often interacted very strongly and may have exchanged mass or thrown their outer layers out of the binary system. This can produce some of the most dramatic objects in the sky, e.g., black hole X-ray binaries. It is difficult to predict how stars behave when they interact strongly, so research at Keele uses surveys to find simpler examples of close binary stars which have interacted in the past, and may do again, but are currently not exchanging mass.
The stellar atmospheric parameters of effective temperature and surface gravity are of fundamental astrophysical importance. As well as defining the physical conditions in the stellar atmosphere, these parameters are directly related to the physical properties of the star; mass, radius and luminosity. We can obtain effective temperature and surface gravity from suitable observations, assuming of course that the models we use are adequate and appropriate.