A Public Lecture by Professor Yvonne Elsworth (University of Birmingham)
Our knowledge of how stars change and evolve underpins our understanding of both the far reaches of the Universe and nearby stars including our Sun. In recent years these studies have all been revolutionised by observations of the interiors of stars. The methods are inherently simple even if they require precise techniques to make them effective. The physics that underpins the method is purely classical. It has been discovered that, for certain kinds of stars, the turbulent conditions that prevail in their outer convective regions cause sound waves to propagate and resonate within their interiors. This leads to small, periodic changes in the surface properties that can be observed. This field is known as asteroseismology. For the Sun, we are able to build seismic maps of the interior and hence make visible the conditions in different regions including the energy-generating core. Several major deductions which had far-reaching implications will be discussed in the lecture.
For stars more distant than the Sun, the information obtained is more limited. However, the recent data from the Kepler satellite has enormously broadened the field because we are no longer restricted to one sample (the Sun at its current age) from the wide range of states that the Sun and stars of roughly similar mass will experience in their lives. The lecture will give examples of how asteroseismology has impacted the study of planets in the habitable zones of their stars and also how we are able to probe conditions in the centres of evolved stars.
Professor Yvonne Elsworth is the Poynting Professor of Physics at the University of Birmingham and a member of the RAS Council. She graduated with a PhD from the University of Manchester on the design of instrumentation to study conditions in the upper atmosphere of the Earth.
Professor Elsworth was appointed to an academic post at the University Birmingham when the field of helioseismology (aka the seismic study of the interior of the Sun) was in its infancy. From those beginnings, she has seen the world-wide development of this novel area. The current unusual state of the Sun and the beautiful dataset from the Kepler satellite make these very exciting times.